How to lift drywall for ceiling up onto a scaffold?

Thanks very much, guys, for all your ideas and for telling me how the professionals do it. I really appreciate it.

(I know the following might be total B.S. because I haven't done it yet, so you might want to put on your waders before reading any further.)

I think what I might do is to install the safety railing (which I have never used!) around the top of the scaffold, and then set the overall scaffold height so the top of the safety rail is a few inches below the joists. Then I plan to haul the sheet of drywall up onto, and lay it across, the safety rail on a ramp made from uni-strut that is attached to the scaffold. I plan to adjust the scaffold's top deck height just right, so when standing on it you can bend over, get under the sheet and easily lift it up to the joists with your shoulders while a second guy screws it to the joists. I'm probably going to cut the full sheets in half because I'm old and weak.

I'll let you know how (if) it works out. Thanks again.