All very good suggestions and I have looked longingly at the Bonewitz at Knob Mountain. But I have a hankering to carve that blank into a Bonewitz myself. I just have to find a way to produce a paper profile of the buststock I can transfer to wood. There must be a way. I just haven't stumbled over it , yet.
As far as trasfer, scan, scale, and print it out at proper size, cut around the profile and tape with transparent tape to blank, after positioning for best grain flow through wrist as best you can. Then just cut it out in profile with a generous margin to account for run-out, etc.. This worked for me -- there may be several better ways! I actually sliced off a 1/2" section that I will clean up and use as a template in the future. If you transfer the paper to heavy cardboard or light plywood and then cut that out, it would be even better, as you could trace around it and keep it for reference. I found the printed picture handy for lock, trigger, etc., positioning.
There was a recent thread on sizing and printing (or otherwise producing) a scaled picture -- you dont even have to have a computer, although it is harder without one.
If it is your first, just use the pre-carve -- plenty to learn even starting there!