i kinda like when i can put it on with the set screw away from the motor body. then the "shoulder" of the pulley acts as a fender, preventing the belt from shifting.
I can't do it with the y axis, because the motor bracket is so thick, the set screw isn't over the axel. (not really sure why it's made so thick. of course to support the motor, but why not a bracket for each side of the motor?)