How come a uniform can't be made of 40% to 90% life fibers? I've noticed that on Kill la Kill that Goku Uniforms can only be made from 10%, 20%, and 30% life fibers. But later on, it is revealed that a Kamui is made of 100% life fibers. That seems like a major gap to me. How come a uniform can't be made of 40%-90% life fibers?
No characters we see can wear 40%-90% life fiber uniforms who cannot also wear 100% life fiber uniforms.

The only people who can wear 100% life fibers are not 100% humans (they have life fibers experimentally infused into their bodies).  No pure humans have been shown to be able to wear more than a 3 star uniform.