advice for side loading 'system' onto a van roof

I’m searching for a two bar side lift onto a van roof.

current commercial offering are fewer than when I last looked 5-6 years back now running up to $1500.
I looked for a winch finding Champion 12003 goo.gl/pe9DUw.
McMaster Carr shipped http://www.mcmaster.com/#standard-rollers-for-conveyors/=1a74ffo, corner brackets, n 1/2" 3M HD electrical tape. Note screws hereon the ground and at Carr are not in the bag.
2 2/4’s up to the DIY full floor roof rack poss covered in carpet should start the project next week.

Have you considered the Thule Hullivator?