Having trouble seeing the need for a zero/low lash coupling on the table drive. There won't be any cases where the table will need to stop in a precise location that I can think of. Normally, the table runs out from under the wheel some small but arbitrary position before reversing direction.
And Bill, are you saying you are using a rack and pinion for the main table drive? I've thought about that on a few projects, but mentally can't get past the upward force by the engagement angle of the teeth. Unless the table is possibly constrained somehow or is just plain heavy enough to negate this effect. I've been under the impression that this is one reason that many of the smaller grinders use a belt drive there. No criticism intended, just sort of thinking out loud.