Brushyspoons: this is exactly the type of profile drawing I make before I build a rifle, especially if I'm using parts that are unfamiliar to me. Everything has to fit in a relationship to all the other components. Your drawing is excellent, and the drop at comb and heel will yield a nice shooting rifle. I think you're good to go, though I haven't compared your drawing to RCA 124 either. Sounds like Rich is on it.
Rather than draw on plywood, I use heavy white BristolBoard card stock. When I am satisfied, I trace the outline onto 1/8" plexiglas with a fine sharpie, and bandsaw out the pattern. With the clear plexiglas, I can lay the pattern on the board and see the grain flow through the pattern.
I agree with a previous poster who said that lop for a flat butted rifle may be shorter than that of a hooked butt rifle, owing to the mounting of these vastly different styles of rifles. I'm 6'2" tall with 35" arm in-seams, and a 13 1/2" lop suits me well. I don't crawl a rifle stock though...I bring the rifle to my eye rather than the converse, and shoot heads-up. With a rifle having this type of butt, I shoot the rifle against my shoulder, not out on my arm.
Nice work.