I put together the universal linkage kit last night.
Basically they consist of of 6061 T6 Aluminum tubing with some high strength 1/4-28 Rod running through the center that you can cut to what ever length you come up with. The rod ends are high quality steel. They come with jam nuts and stainless nuts and bolts to bolt onto your modified shift lever and brake lever.
The installation plan is that you can mock it all up using the threaded rod being sure to keep as much thread engagement as possible into the rod ends. After that disassemble the ends from the threaded rod and measure the rod length. To cut the aluminum tube simply subtract 2 inches from the threaded rod length and cut. Be sure to tighten the jam nuts onto the tube to about 10 - 15 foot lbs. because the tension compression of the tube and rod adds to its strength and is most important on the brake side. This is the cleanest way to make your own linkage if all you have is a hack saw and a drill . If you want you can brush, anodize or polish the aluminum tube for a custom look.
I have a set up at Cafe Racer Ypsi on display if you need to touchy feely a set.