I've been paper patching for about 3 years.....and handloading for about 8. I found that getting good results with PP is easy.... so I'll never go back to jacketed bullets (or just plain cast ones). I patch for the 8 x 57, very similar to (and the grandaddy of) the .30-06. My PP loads consist of a flat-nose 175 grain bullet...and I get just over 2000 fps through my 18" barreled Yugo M48.....with accuracy of 1.5" or better at 100 yards. Actually, the load will shoot into an inch, but I can't duplicate that with consistency (someone with better eyes and better skills probably could).
1) You can PP grooved bullets or smooth-sided ones. Either will work....and either can be accurate. Obviously, smooth sided bullets have an advantage at long range. But, grooved ones will do just fine. I shoot a grooved bullet myself.
2) Are you referring to how to CAST the bullets.....or just how to wrap them ? I don't cast myself, as I am partially disabled and my living environment doesn't permit it....so I purchase my bullets. I assume that you are just asking about PATCHING, because you said that you shoot "mostly" cast bullets. In a nutshell, using trapezoidal bits of paper, you wrap the bullets with TWO layers, so that the patch finishes right at the "bulge" from the starting point....in other words, two wraps with no overlap on the second (outer) layer. Others have tried 1 wrap, 1 1/2 wraps, 3, etc...... and it never works as well as the "standard" 2 wraps. So, I'd suggest just sticking with that.
3) The important issue is the final wrapped diameter. How you get there is up to you. Most smokeless powder paper patchers have the bullet at approximately BORE size....then paper patch to GROOVE diameter, or up to 0.001" over that. Usually, it does not pay to go larger than 0.001" over groove size. As well, smaller than groove doesn't usually work with smokeless, either. Black powder PP shooters usually use wrapped bullets at bore diameter. However, BP causes more obturation than SP does..... BP bullets are usually very soft..... and they have to deal with the BP fouling issue. So, what they do is NOT directly analogous to SP paper patching. Since the final diameter is the important issue, what you do is choose a combination of bullet size and paper thickness, to get there. Bear in mind that many papers will stretch and shrink, as you apply the patch and they dry, respectively. So, experimentation is always necessary, to be sure of the final product. I buy my bullets at 0.324" diameter, then size them to 0.314" (which is approx. bore diameter in my rifle, as it happens). Then I wrap them, two wraps, up to a final dry dia. of about 0.3235". Then, as a final step, after lubing the patches, I size them to 0.323".
It is always a good idea to slug your bore, in order to get an exact idea of BORE and GROOVE dia...... this will make things easier. It is well worth it, in the long run.
4) You can use ANY paper that will do the job. Some use cigarette paper...... some heavy-duty drawing vellum. I found, early on, that ordinary lined, loose leaf notebook paper works just fine....and is the right thickness for my application....so that is what I use. Also, since this paper has some cotton content, it has the necessary strength...and stretches (and shrinks when drying) allowing me to get tight patches.
What you will need to do is plan and experiment. For instance, for your .30-06, the BORE dia. should be about 0.300"....and the GROOVE dia. should be about 0.308". If that is true, depending on the bullet you choose to use for this, you should likely start with a bullet at about 0.300". That leaves 0.008" for patching. 4 layers (2 complete wraps) of paper, 0.002" thick, will give a final dia. of 0.308". Lined notebook paper is usually more like 0.0025" or so thick, so you'd end up at something like 0.310".....IF the paper didn't shrink, as it dried. Since it normally WILL shrink, you will end up at something between 0.309" and 0.310". That MIGHT be fine for your rifle....or it might not. Probably, you'll need to go no larger than 0.309". So, you could try a thinner paper......OR, simply run the wrapped, lubed bullet through a sizing die..... to get 0.309"....or 0.308" ....or whatever will work best. As I said, you do have some experimentation to do. You CAN use an oversized bullet, wrap it, then size the whole works down to your final diameter. Some people do it this way. However, you will want to avoid too much sizing. For instance, for your .30-06, you wouldn't want to use the bullets I use - (0.314", wrapped to 0.3235")....... sized down to 0.308 - 0.309"......that would be too much and you'd likely affect bullet concentricity. But, there is no need to pre-size your bullets, if they drop from the mould at the RIGHT size. So, if you cast at 0.300"...... then you are good to go. So, you see, there are multiple ways to get there.....but the important thing is the FINAL size.
4) I think I covered this already.
5) The shape of the patches, believe it or not, doesn't really matter.....up to a point. Yes, the patch will need to be some version of a rectangle, in order to wrap a round bullet....but the angle on the ends does not matter. The 45 degree trapezoidal patch was developed because the 45 degree ends made it easier to start rolling on the patch. You CAN use other angles....any angle you choose. I use 30 degrees. Why ? No technical reason.....I just started out that way.....and it works fine. (It ain't broke, so there's no need to fix it.) Some will claim that you must use an angle that coincides fairly closely with the rifling pitch of your barrel. That has been disproven by experimentation. You could even use NO angle - true rectangular patches (some have done it). However, the angle on the ends just makes it easier, so I'd suggest you use some sort of angle (exactly what is your choice). 45 degrees is easy, so why not start there ? Note that, whatever angle you use, BOTH ends of the patch MUST be uniform (same angle), in order for the patch seam to line up - and you DO want it to line up, as much as possible. You also want to experiment with patch length, so that the final seam will be as tight as possible. A SMALL gap is OK....say 1 /32" or so, but the end seam of the patch should be as tight and uniform as possible (for greatest consistency.....and best accuracy).
6) Wet the patches with plain water - just PLAIN water. Others have tried all sorts of concoctions.... but plain water always ends up being best. How long you soak the patches (how wet you get them), will depend on the paper used. Tougher vellum papers will need to be wetter..... lined notebook paper, less so. I don't SOAK my patches..... they tend to tear too easily. I just DIP each one, then remove the excess water with my fingers, right before patching each bullet. Now, as to the "sealing" of the patch edge, or final seam..... that is a subject for debate and consideration. Most do nothing here, just let the tightness of the wrapping and the base, keep the patch sealed. It is easy with large-calibre bullets, with the right paper (as it is easier to wrap them anyway). For smaller calibres, it gets tougher. So, from the beginning, I have used a TINY amount of yellow glue to seal my patches. Some blanch at the idea, but it works for me. I simply smear, with my finger, a very THIN coat of yellow glue on the last 1/8 - 1/4" of patch, before rolling it closed. So, I always get nice, tightly sealed patches, that never come apart (before they should).
Glue is a controversial topic, however. You definitely NEVER want the patch to be adhered to the bullet. The way things are supposed to work is that - the rifling cuts the patch, as the bullet travels up the bore - then the patch strips cleanly off the bullet, just after it exits the muzzle. You don't want to do anything to change that scenario - as it will ruin accuracy - NEVER should the patch stay on the bullet, all the way to the target. You see, what paper patching really creates is a "sabot" for your cast bullet. We are simply making a sabot of paper (and directly on the bullet)....rather than a pre-manufactured sabot.
I should say something about bullet bases. What to do ?....... fold over the patch, to form a flat base.....or twist a tail ? This is VERY controversial. Many say and I think that most agree, the base of the patch should be as consistent as possible. This would indicate that folding the patch over to form a flat base would be best. I have tried it both ways, extensively. It is MUCH easier to fold over the patch to form a flat base on LARGER diameter bullets. With something like the 30 cal..... or 8mm, you will find it easier to twist tails. I do both, but tend to twist tails, the snip them off after drying (and flattening the base against a hard surface)....most of the time. I have found no accuracy difference, at least, in my rifle and at the distances over which I shoot (generally, no more than 150 yards). I do believe that folded bases are probably better, simply because of more consistency, in the end - but I can't prove it.
7) I've covered this already, but I'll reinterate. All manner of techniques have been tried - one wrap, two, three.....wrapping a severely undesized bullet up to another diameter, etc. But, in the end, the standard TWO wrap technique works best. With paper, I'm sure it always will. So, you can play around with wrapping all you want. But, in the end, you'll most likely come back to the "standard" form.
Well, there are answers to your questions - such as they are. You'll probably have lots more (paper patching is both simple..... and very complicated, at the same time). It occurs to me that a few simple drawings might help - or photos, for that matter. I do not have a suitable camera.......so I'll make up a few simple drawings illustrating what I've talked about (above)..... and post them on this thread.
I hope that I've helped you.
Edit: One more thing. Undoubtedly, you've heard that jacketed bullet velocities are obtainable, with paper patched cast bullets. This is true, with certain limitations and specifications. The velocity you will be able to achieve with PP depends on the relative hardness of the bullet alloy used - just as when shooting "naked" cast bullets. The higher the BHN (bullet hardness number), the faster you'll be able to go. In your 30-06, even 3000 fps is obtainable, but with a bullet alloy which is so hard (and therefore, brittle) that it will shatter on impact on most solid substances. So, really high velocity PP bullets are NO good for hunting. For good expansion on game animals, a BHN of not too much more than 15 is recommended......with that alloy, you'll be able to get a little past 2000 fps....perhaps 2200 or so. I can get to that velocity with my BHN 12 - 15 PP bullets, but I get much better accuracy at around 2000 - so that is the point to which I load them.