This plate is designed to allow the Trail Tech Vapor to be mounted while still retaining the stock turn signal/neutral/hi-beam indicator lamps. It also has mounting holes for the ignition lock and a 12V cigarette lighter-style DC outlet. It uses the mounting bracket for the stock instrument cluster, so a S or SM model is required (the E model doesn't have an instrument cluster, hence no bracket).
I modeled the entire instrument cluster in 3D. While not strictly necessary, I find it helps a lot to visualize the size and fit verses designing in 2D.
Once the design was finalized, I sent it to Ponoko for laser cutting in 0.193" Delrin. I had originally envisioned the plate in 0.125" aluminum, but it was cost-prohibitive in single quantities. Delrin is a good choice for this application; however, the 0.193" thickness was too thick for the mounting clips on the ignition lock cylinder. A quick pass on the router table removed the extra material, and future plates will be made from 0.125" thick material to avoid this problem. I am exploring having a run of about 20 mounting plates waterjetted in 0.125" aluminum, so if you're interested please let me know.
I installed the plate with stainless 1/4"-20 fasteners. 10mm fasteners could also be used, and would be preferable due to the rest of the bike being metric. The installation re-uses the existing mounting bracket and rubber grommets. Standard nuts are used as spacers to raise the height of the instrument cluster. Locking nuts with nylon inserts are used to retain the mounting plate, ensuring they don't vibrate off.