Joe, there definitely isn’t any advice in the old docs for doing that. I ended up creating a hybrid system, similar to how the clutch works. The original single master cylinder feeds a slave cylinder which operates a new electric high power dual master cylinder from ABS brakes (www.abspowerbrake.com). ABS fabricated all the brackets for me. This also allowed me to eliminate the Hydrovac (which I might use as a booster for the clutch).