So far my aluminum couplers seem to be printing pretty good but because it's a new build I don't have a comparison.
I have been thinking about the couplers and how the Prusa style printer has been using them and as far as I understand totally wrong. Those springy couplers are meant to be for misalignment and smoothout drive transition from forward to reverse etc. but should be used from motor to lead screw but where the lead screw is held by a shaft mount. Something like this picture.
All small CNC routers and laser cutters I have seen use them like this... so makes me think that wouldn't be hat difficult to incorporate into a Wilson design for the Z axis.
I am also wondering about combining this setup with 1 motor and belt drive both Z axis. So instead of a coupler just have a pulley and the motor under the hotbed. People who use this setup say they get better Z axis movement and don't have the issue of motors going out of sync.
When you think about it both Y and X are belt driven and we are getting dimensional between 0.1 and 0.2 error at the worst on a good setup.
Plus 1 motor cheaper and the old style handle on the Z axis (like the old Makerbots) and wind the Z up and down by hand quickly and synchronized... and maybe other things.
Maybe some ideas for the Wilson III.