I know that this is an old thread, but here it goes.
#1 Please describe your optimum prone position for best accuracy in the field. Angling (30-45 degrees?) to target or torso in a straight line?
Last I knew military was teaching straight line of mat and weapon and body. it helps keep that natural POA in a good direction, maintain consistency and most importantly of all absorb recoil.
#2 Please describe the position of your feet - flat to ground or upright on an angle.
Call it toes out and heels in. Relaxed to reduce movement.
#3 Please describe, if you have not covered this in #1, the position of your elbows, head and neck.
Elbows what ever is most comfortable so I can hold for a long period of time for the right shot, usually a bit out and I am controlling the back of the stock with my left hand. head and neck near vertical it is a bit uncomfortable after a very long time but if you are looking through the scope for two hours I am sure any position would get tiring. Usually at the range is when i get the worst crick but occasionally in the field when the target and wind are not cooperating.