Different woods,different plans. Osage, I would start at 1.75". Some recommdend 1.5". But I come underwieght there.

Hickory, you can start at the fades at 2.5-3"

There is a trick for laying out a curvy osage pyamid. Trying to figure out how to explain.

First, have you read the trad bowyers bibles vol 1 yet? Or simular?

You know you have to lay out an osage bow by finding center?

Hickory, you can violate that some.

1.)Draw your center line down the stave following the grain.
2.)Lay out bow handle. I like my top limb to be 1" longer. So for a 68" stave, you figure 4" for handle, 1.75"-2" for fades. Bow center will be 34"+0.5". Lay out handle 1" wide or more and fades to start of pyamid.
3.) Next section out bow limb in 8 equal segments
4.) Lay out tips, I like to start at 1/2 and narrow last.

I will try to take a picture of the way to lay out the rest.