For 3 lead screw independent motor leveling I would use the cantilevered bed frame arrangement so that there is some room for flex during the leveling routine. If there is no flex, there will be binding. For the single motor setup, I would recommend using the front beam and all 4 corner wheel carriages for the rigidity. As I have done in my build. I use Z hop occasionally. It does work, though I try not to use it because the bed is very heavy and it puts a lot of strain on the motor even though there is a 2:1 gear advantage and the 1mm pitch lead screws don't have much rotational resistance. Sometimes it is needed though, and I haven't noticed any issues from backlash or positioning errors.