[SMFREY]

That sounds like a challenging issue to resolve
Have you thought of making the PWC rack on wheels that can be secured to a trailer
This could resolve several issues
Loading and unloading PWC in and out of trailer and water
Weight shift when Quads not on trailer they can be moved forward
Possibly look at the small trailer/hand carts used for the snowmobiles and figure out how that can be used to raise and lower PWC on small hold rack
Just some thoughts may be a simple resolve
Good luck
Ray