Originally Posted by
Precaud
Some of them are on eccentric shafts which allow the gear mesh to be fine-tuned.
I like this. Having some way to fine-tune the gear mesh would be awesome. I was kind of in guess and check mode.
Originally Posted by
Precaud
My general POV is to use the tightest coupling that allows the gears to rotate freely, without any binding.
I did it based on visual observation of backlash (which was harder to do than I expected). To do it again I think I would take your view. That is, set it a little tighter than I think I can get away with, check if it turns smoothly from the handwheel, run it under power and make sure no howling. If any binding or howling, make it a little looser and try again.