Hmmmm...I'm so metally buried in Native American designs that I forget that there are many things that are unorthodox about this bow.
First of all, the cross section is oval. This is not the most efficient design. Both the back and the belly are more likely to fail than with a rectangular-shaped cross section. Two things prevent breakage in this case. One, the cable on the back reduces the strain on the wood tremendously. Two, ashe juniper is excellent in compression. The rounded belly does compress excessively though, resulting in higher than normal set. This is not necessarily all bad. The bow is much less likely to explode. It may just keep taking more and more set until it loses all of its spring instead of breaking.
The thread is also NOT the same as sinew. The thread actually "stacks" much quicker than sinew. When I make the "real" bow using real sinew, I expect less draw weight for the same amount of mass.
There are no nocks. The string stays in place for three reasons: the tips taper sharply in the area where the string is attached, both ends of the string have slip knots, and the wrapping on the tips helps to hold the string in place...due to friction and the irregular surface.
I am using a pinch grip with three fingers under the arrow. This causes the lower limb to bend more on a bow that is symmetrically tillered.
The 20" draw is quite short and seems very inefficient. For the purpose of close range shooting, this draw length is adequate, however.
Ashe juniper is not a well known wood. Even in its native range, it's called "cedar" and is considered a trash wood or an invasive species. Also, the heartwood on ashe juniper is great for making pencils but pretty much junk as bow wood.
OK, that's enough of my ranting.