The sharp edges and spacing between the tilt axis and the upper rail are just right to somehow pinch my finger tips when I'm tightening it after adjusting the tilt. I have new and old blood blisters on my finger tips. It's happened more than once.
May I suggest humanizing all your knobs. More rounder. More spacing between knob and rail which can be achieved by rounding up from the bottom.
Also, the knob for the camera plate and/or T-adapters could be smaller and a simple knurled texture on the edge would do. The current modified cross shape is just big enough to prevent moving my camera forward enough to get two of my wide angle adapters to the nodal point. Yes I can turn the T-adapter around but then I can't move my fisheye far enough back.
Life is hard -- then you die...