Are PU coated ball bearings in place of normal bearings an option?
I doubt it for a few reasons. Do you have a specs link?
PU 608RS 8227 not available …
Weird. That link wants me to sign in. When I do, it gives me an.error message (in Italian, maybe?).
Measures matching and link should work.
I bet these would be lovely for Zen XY.
For CNC a rigid bearing will be better.