We switched to 48 pitch gears after stripping too many spurs. With 12 and 14 turn motors we use 96/22-25. Seems to work well.
The TA04R kit is awesome. Wish I had known about it before buying my 4Pro and hopping it up. A friend who placed second at the TCS Nats ran the kit and says the carbon tub is stiffer than the plate chassis, even the saddle pack one. We just rebuilt ours to use the Pro kit bottom stick pack plate and graphite top plate, which is stiffer than the saddle pack set up.