thats a nice conversion, as said very compact. I thought there was a one way on the front of the TF
The one way is built into the dogbone cup, so when I converted my twin to the revo shafts, I got rid of it.
I played around with a few gears and the Savage X spur will work, it's just a little big. I had a 49 tooth kicking around. A 46 tooth would work perfect.