We really can't give electrical advice (or advice on rigging, scaffolding, ect) on this forum due to the liability issue. I can at least give you an "idea" of your chance of success when taking the unit to a qualified technician or shop:
The fact that the owners manual shows that you can reassigned channels to different phase legs is a good sign that each has it's own ramp generator. The fact that there is multiple neutral terminals also is a good sign. Here is the pitfall to watch out for. When you are operating dimmers off of standard wall outlets, the neutrals can have no interconnection! For instance, if
channel 1 is on one plug and channel 2 is on another, the neutral for channel 1 needs to return to the same plug as the hot came from. Most dimmers have a buss
jumper between the neutral terminals. This produces a fire hazard if you are plugging it in multiple wall outlets. Although each outlet is protected by a 15 or 20 amp
circuit breaker, only the "hot" wire is protected. Here's an example of trouble: You happen to plug your channels into two outlets that are on different circuits but on the same phase leg. Unknown to you, there is a defective or dirty plug that interrupts the neutral connection on one of your plugs. Everything seams to work correctly BUT you are unknowingly sending 40
amps back through one 12 gauge wire through one prong on a 20 amp plug!