I'm installing a Fadermate system now and having a rough time. The install seemed to go fairly smoothly - the system appears simple overall. There is not much room at all between the bottom covers and the channel pcb's, so the Fadermate boards are sort of floating in a tight space, which I don't love.
I was unable to calibrate the system on my mac, but it worked well enough on PC. When I asked the Fadermate team, they said to just use a PC. Not the most thorough support for mac, but I have a laptop available.
SSL boards require an additional card from Fadermate that they include for each bank of 8 faders. It's purpose is to smooth out the audio taper of the motorized Alps Audio taper to better match the SSL VCA fader behavior. To power it I tapped into the + and - 18v rails from underneath a bucket of channels. They send a separate 3 page PDF describing this procedure.
The main issue I'm having is that the Fadermate system seems to be attenuating the signal by about 65db. The signal passes, just drastically low. Automation via HUI works great. To Fadermate's credit, they have been very responsive, patient, and helpful. Unfortunately they also appear to be stumped. They do tell me that they've installed in SSL's before without issue and I do believe them.
My issue stems from the VCA conversion board. It puts -5vdc on the top of the fader, which should be at 0v. The fader passes audio fine without the VCA board, but only the top 25% of the fader is useable as the rest is silent. I'm hoping I just did something wrong in the install, but so far no culprit has been found.