I am still a rookie have only made 7 Osage selfbows.
One one my best shooters is a pyramid style 63" NTN, 58#@28". 
It is 1-5/8 at the fades with a straight taper to 1/2" at the tips. 
Have never checked speed but I shoot lots of 3D against recurve
and laminated longbows with no problem. 
I have been leaving last 6-8" of the outer limb stiff to prevent possible 
Whip tip which could rob power and cast.