This is a cool thread. I'm glad you got one that fits Thurin.
I think the size difference on the tapered vs non tapered Bushfingers up there are more due to the original thickness of the material. That non tapered one just has a thicker handle. I vary my handle sizes on the same model a lot. This is due to two seperate factors. One, there are folks that like them thin and folks that like them thick. Not a lot of knifemakers will cater to the thick handle guys, so I make a point to do so. Second, as a knifemaker, when you hand grind or carve things, you tend to chase. This side is too big, now that side is too big. This affects the grind heights, the taper thickness on the tang, and handle shaping on frustrating days.