wall between attic space - only one layer of sheetrock

I have an upstairs room and 3 sides are wall that separate attic space. There is only sheetrock on one side with insulation on the attic side held in place with a netting material. I have read the faq on wall construction and it doesn't actually address or provide a STC for this situation. The question is it better to add a second layer of sheet rock in the attic side. (which would be difficult to do and impossible to ensure it is totally sealed) or add the second layer of sheetrock on the room side? Would RC for the second layer be better than two layers with GG?

Adding the sheets on the room's ceiling will keep 2 leaf. Adding them on the attic side will create an extra leaf. However, since attic space will prolly be big enough for a person to stand straight the leaf thing will be kind of different here. (as in, those extra 2 inches of "spring"space will just disolve into the big "spring" that the attic already is) imo, adding sheets on both sides will improve mass. hanging sheets on the ceiling is more tricky then adding them as "floor" tiles.