Projector Screen Retractable

How much weight can I hang from a drywall ceiling with a toggle bolt?

I have a retractable projector screen that I would like to hang from my ceiling. I live in an apartment that is an all steel structure. I was told not to drill into the steel support beams as this would affect the sound dampening, but I am allowed to drill into the drywall (which they say is a double layer). The screen weighs about 20lbs, with an attachment point on each end. So each toggle bolt will have to support 10lb plus the stress of pulling on the screen to lower it. I stood there with my drill for about 20 minutes having second thoughts... i'm having visions on the screen coming crashing down bringing half the ceiling with it. Do you think the drywall can support the weight?

You've got those screws with the little spring-loaded "wings" that pop out behind the drywall? Good. They come in different sizes. If you get the kind that has "wings" that are over an inch long apiece (go 1.5" if you can), they'll hold 10-15 lbs. with little problem, especially if the ceiling is really double-thick.

Centor® Architectural's S1E Eco-Screen™