I'm not visualizing what your saying perfectly, but I think that's one of the ideas I had in mind.
In your example which side is the raised side? Which side does the shlok sit on when rolled up? North or south
Correct me if I misunderstood. Your shlok is sitting on the raised side when it's rolled up.
I was thinking of putting the rolled up shlok on the lower side that way I only need one string to unroll it and letting gravity roll it back up by releasing the string and it will roll back up with the shlok.
When rolled up i personally have it on the south side (and it's the lower side as well) with this system it really can be done either way truthfully.
The reason I have it this way is because I want the shlock rolling up (opening) away from the succa so all extra water thats on the tarp with flow off the succa and not into it. (I have the succa on a deck, so the north side is a house-and the pvc can't be rolled past the succa)
The second idea you mentioned, is what many people do, I personally don't like it because the slant must be much steeper, in contrast having another string isn't such a big deal.
That being said, I've never done the other way personally, so I can't tell you if it's better or not.