hanging backdrops

"How To Fold A Backdrop!" (with special thanks to "The Backstage Handbook" by Paul Carter)

I've setup a truss frame from which I'll hang all kinds of backdrops. The frame is 20' wide and suspended from a parent frame with 2 hoists. Without using 4 hoists for a 4-point lift its challenging to level the subframe. The attached photo may help to explain. My current idea is to attach the...