Hey John,
you mean Ball Screw Nut hits Ball Screw coupler on stall homing?
The optional Onefinity 80 mm mount is 2″ (51 mm) high high and Z linear bearing should be 2.75″ (70 mm) long. I assume you have the same measurements on your machine ?
Yet I haven’t seen that someone was able to attach these useful bump-stops on Z axis, only on X and Y:
Also Stops for Homing
The reason to mount these bump stops were preventing stalling the linear bushings against the machined parts because there is a oil-wooddust mix building up with time on the chrome-plated hollow shafts which affects stall homing repeatability.
Did you have problems to loose the two set screws as mentioned here: Swapping the Spindle Mount?
Did you reuse the same set screws when reassembling and was this difficult?