Which would increase resolution?

Hello,

I was wondering, has twenty teeth been calculated as being the most efficient at achieving the finest resolution on the "belt type" cnc routers, specifically the OX?

What factors go into calculating resolution for a given setup with respect to the number of teeth needed for optimizing pulley/belt/stepper ? On either side of the 20T pulley, what at the effects of say... a 16T vs. 24T pulley the same system?

Thanks,