Changes I would make if I was doing it over.
The winch set up was left from my 1955 Thunderbird and that top was very heavy not light like the Viper.
1. So I would think about mounting the top (pulley) location on a slide of some kind so the car did not have to be parked exactly in the same spot every time. Not a big deal since the viper top is light a and no painted surfaces near the top mount to worry about scratching.
2. No need for the MB top lift I just had it, it is too narrow and couldn't use the drip rail clamps anyway so a single length of 1 inch square tube would do. Weld a center loop as you would want a bolt come all the way though it to scratch you top.
3. I would make the end pieces a little wider, that was just some aluminum I had I cut in half, one again I would kist weld some 1 inch square tube on the ends about 18" long
4. The web straps were left from the T-bird top lift i had put the rope on the ends to tie them together on the birds roof so I could put the cover on it. The birds top was very back heave due to the rear glass and c pillar so it use a 3 point strap one across the front and third on under the rear window, that was a pain to put in place so I left in it most of the time. so I think I would think about maybe hook to positive hook the straps in or maybe even a rigid support that I could hook both sides from one side, like a carpet cover 1x2 or plastic pipe.
5. because the viper top line up is easy not hard like the T-bird, I think I would do away with to added pulleys use to slow down the travel or control the speed with a rheostat since the top is so light.
6. lifting it so high is not really necessary on the viper it was on the bird as the rear window had to clear the radio antenna.
These are just some thoughts, I tend to make things out of what I have laying around the garage and design on the fly and sometime late I think of better ways to do it.
As I think about it you could make the whole think about a 2 inch schedule 40 plastic pipe, by using fitting you could do it all from one side. leave to parallel ones on one side unglued and the perpendicular one of the other side unglued for and easy slide together fit. If your not sure what I am talking about i could draw it up for you,