Hey Mike,
this is a known Onefinity Z Axis Design Issue.
For the time that I intend to use the Onefinity CNC machine, I’m thinking of making a different z axis. @TMToronto already did that with success.
Regarding the limits, you can adjust them in the corresponding MOTOR section of the controller. You may also think of retrofitting inductive limit sensors to get rid of unreliable stall homing.
To avoid carriages bumping against the linear bearings when using stall homing, you may also think of Bill @Machinist 's solution:
