If it's the boards that are bad, you might try
fixumdude's boards. I don't know if the FW boards were standard arcade boards (fixumdude's should work) or not (??). Could you post some pictures of the board to help figure if it is?
And while you're at it, would you mind posting some pics of the spinner, just for show?

Info on number of teeth or gaps per one rotation of the knob, number gears (any any), and any other info would be awesome too. Thanks.
Anyway, I'm guessing you're going to keep the FW game, yes? I wonder if the
TT-HL in slave mode will "work"? Very different resolution, though, I bet. Hmm...
I'd guess the GGG and ultimarc knobs should fit. How close in the
GGG Big Blue to the originals?
Good luck on fixing the controllers. That was one of my favorite games as a kid (and isn't now only due to I don't have the original controllers, or at least something very much like the original CP).