I'm running this Traxxas 60T, #2519, on one of my cars:
It needs 3/32" diff balls. You may need to open up the center hole a little with a reamer, and/or add a 1/32" shim to compensate for the smaller balls.
I have also run the small Robinson machined spurs by chucking up the diff rings in a drill press and grinding down the OD on the diff rings. But of course that won't change the diff ball pattern.
None of these things were on an XRay, but I'll bet you can kluge something together similar to the above.