G'Day Matt
I have a simple system. Two pipes hanging from ropes above where I park the car. (in the shed)
Mine holds 3 sups. The ropes allow them to move, so easier to put the sups up.
I have them on a simple pulley system so they can be moved up and down for various reasons. (with a second set of fail-safe ropes attached)
Also added 3 separate sections of a larger diameter pvc pipe on each rack with bubble wrap around to act as a roller. Works great, particularly with the DW board.