So Z axis
-easier for different stepper shaft lengths.
-coupler has bigger screws, more “meat”.
-coupler is knob combo. less hardware
-knob is larger diameter than the last, easier to turn.
-a few mm more grab on each side.
-??dual mounts keep the z axis more true, when combined with the upcoming tool mount???
-Zaxis screw can be much shorter, hopefully keep it cleaner.
-Way easier to get at the znut lock as said before.
—Z screw axis is further from tool, I think, not ideal but I rather have the tool closer and the screw further. Tradeoffs…