Haven't made one, but I'm having a look at it. Doesn't look like there should be a set handle length, to me, as it fades consistently to a center. If I were going to make it, I think I'd be focusing on getting that sweeping fade right in the tillering of the bow. It looks like it should be a sorta semi-rigid handle. I'm figurin' that the dimension has to be played with in consideration of the wood your using. From fade and to fade end, maybe 9-10 inches? You going to use hickory?