Console Project, Part Two: Fader Card-1

I got some faders! More specifically, I got the Bourns PTF01-152A-103B2 model. Basically it's 10kOhm, 100mm travel, linear, AND, most importantly, DUAL GANG. I only got 8 because yikes these things are expensive but also, I'd like to multiplex these in banks of 8 anyway so this will work fine as a starting point. But Matt! , I hear you say, you SPECIFICALLY said you wanted motorized faders in Part One. Those are NOT motorized!!! Fair point, imaginary reader, they are not. But, borrowing heavily from the Behringer X32 motor fader design, (and having a boatload of brackets cut on a waterjet...more on that in the future) this SHOULDn't be that hard of a conversion. These were ~$8 a piece and I expect them to cost less than $20 to fully transform. Why on earth then, would I not buy the pack of 5 pre-made X32 motor faders available on Amazon PRIME of all places? It's $100! That's $20/piece and it's pre-made! Simple, actually. In the first paragraph, I state...