I'm with Pat. I've never had to back a hickory selfbow.
I have one (possibly favorite) hickory bow thats 62" long, near 2" wide, and draws about 45# @ 25". The back is ugly, roughly finished, gouged scratched, and dented and it's never given me a single complaint. Granted it's fairly overbuilt for draw weight and length.
Especially wiht a toasted belly, Hickory really makes a fantastic self bow