Very nice design! What was the trade off in weight capacity to have the bearing upside down? We use a lot of round rail linear and the trade is 75% capacity to run upside down, is the rail you are using similar?
We have a DT gantry (mechanical parts) and will probably need to do something like you have done soon as the cam roller set-up we have now is a PITA, can't let your mind wander and forget to sweep the rail.
WSS