I would say copy the way Dunlap's cut their blanks. I have bought over 50 from Wayne & have been able to fit every single rifle I have tried on his blank patterns. If need be, I could copy one & mail it to you or probably he would do the same.
What you are trying to do is important, as adding wood is not an option. I bought 2 blanks from a dif. vender last year that have awesome grain & stripes & etc., but only to find out I am VERY limited to what I can make with them, because the vender cuts too much wood out of the belly of the buttstock. So if you are making a roman nose or a Lehigh or something of that nature, you are fine. If you want a Lancaster, York, or even a Tenn, you are SOL as there is not enough wood in them to get the buttstock correct.
And I suggest 4 people on the band saw, if you don't have a roller or long bench behind the bandsaw. One to help you thru the saw with the planks & one to catch the cutoffs as they come thru the saw & not catch or pinch the blade.
I would say 3 people at the min. & someone with some strength & brains. The planks are heavy & want to twist as they come off the saw, so you need someone strong enough to handle them.
I have 9 black walnut planks that are 3" thick, 28" wide & 9' long that I need to get planed to see the grain well before I cut them. Problem is finding a planer that wide. So far 22" is the widest I have found. Oh, have have 2 cherry planks as well that are 3" x 24" wide, 6' long. Looks like I may have to try a electric hand planer to at least get to where I can see the grain, cut the blanks out on the band saw & then have them planed & cleaned up.
Keith Lisle