I would go 66 tip to tip that would be about 64 n-n 4 1/2 handle ,I usually go 4 in. handle
and 1 1/2 fads.[I don't do the Torges method]
I would go 1 3/4 at the fads and tapper
to about 3/8 at the tip.You can narrow them down a little later after you have it tillered.
I would rough the limb thickness to about 5/8 to start with,this is a pyramid style and the limb thickness will stay close to the same along the limb.It will thin some but the limb tapper
will take care of most of the tiller.It will probably wind up close to 3/8 thick so you should
have plenty of wood to work with and should make 50 plus with no problem.I keep the belly flat
with just a little chaffer on the edges.There are lots of way to do it but this is how I do it.
Hope it helps.
Pappy