[thefro526]

This drive train is pretty awesome, we used some similar concepts on our Drive in 2013 and it ran really well.

If I remember correctly (It's been a while) you don't need to drill out any of Vex Pro's 1/2" Hex Gears to clear the tube axles. One of our wheels per side was driven the same way that you're proposing, and all we had to do was bolt the gear onto the side of the wheel and go.

We also noticed the same wear characteristics on our Versa wheels, we ran an 8WD with the outer corners raised 3/32", and got some fairly even wear on 6 of the 8 wheels, but after a while the wheels would wear enough to make the drive sit on all 8 wheels which was solved by swapping the front and rear pairs. (sounds like you did the same thing)

It might be worth looking into the viability of using a quick change gear pair in between the Transmission and wheels. There are a handful of available ratios that have a pretty nice spread for tuning the drivetrain's final ratio.