Hmmm? I never touched those. Guess I should eventually...
Oh well, those were apparently not the glaring problem - With a bit of debug using the original Slim Wheel GMF file, it turns out the Slim Wheel CFL was an busted one I thought I got rid of 5 CFL updates ago. Somehow it was overshadowing the text file I intended AND had put into the correct place to be complied.
It's weird, but it works now. With the stock GMF anyway.
EDIT: Yeah, the ACTUAL GMF doesn't work. Invisible 1kg thing with an attachment point. Very strange. I'll do what you said.