This is a cleaver idea. He really gets to the problem of most camera rig designs. The extra unnecessary counterweight on on the back of the shoulder pad.
Most rail systems are constructed from 15mm DIA rails, which are crazy expensive. That’s fine for short rails used to align optics, but it is equally crazy to construct rigs, stabilizers, and other components from 15mm rails. The JuicedLink DIY product line is dedicated to using 5/8 inch DIA (0.625″) Aluminum tubes.