White woods can make good elbs but keep the belly flat.
rough out dimensions for 50#ish would be - keep it at 74 and cut nocks at 72", handle section 4 inches, 1 inch above center, 3 below.
1 1/4 wide in the middle 12 inches, 4 inches either side of handle.
Then taper to 3/4 wide at 8" from the tips.
Taper to 5/8ths at the nocks.
See how set goes and if you have more than 1 inch by 20" draw, heat treat the belly and narrow or 'trap' the back.
These bows should have only a fraction of bend at full draw in the center section do not let it bend in the middle early on in tillering. Too much bend in the handle will lead to it being shocky. The bend should increase as you move along the limb - elliptical tiller. Narrow the tips if/when you fit horn nocks/overlays.