One of the last items on the List from the Certifier was to have a adapter plate between the new brake booster and the older master cylinder.
I didn't have any means of milling a plate form steel or nylon so I decided to make my own by using epoxy putty. Its a two part putty that you kneed together and it sets like rock and can be filed, sanded, drilled and painted. Since the plate is not for strength, but for mounting support and just under compression it should be ideal.
Basically I kneed up the putty and with the use of the foam template form up the plate at the right angle and made sure it covered the full area of the master cylinder mounting flange. Once it was shaped and the epoxy started to go off I put the master cylinder and booster together to make sure of the fit.