Mounting heavy ceiling clouds, any dos and don'ts?

I don't particularly like them, even though all the dying and dead bugs and spiders that collect in them are kind of amusing.... prefer a ceiling diffusor

Good screws into the studs should be just fine. Believe it it not, heavy duty drywall anchors will hold. The Lag Bolt type anchors will hold something like 250lbs each…however you need high quality, 5/8” dry wall or better. I personally wouldn’t trust the dry wall anchors for holding something heavy above your head…

Fun story…one time I was hanging big commercial JBL speakers for an install, they were up about 20 ft in a bar renovation. The contractor gave us the ok on where to place them. We used heavy duty lag bolts. The next day we came back to the job site and 3 of the speakers had ripped out of the wall and fallen on the ground. They could have easily killed someone. Still attached to the speaker bracket were huge chunks of dry wall. The lag bolt anchors held just fine…it was the dry wall (double layers of 5/8”) that broke. That’s when the contractor told us that the entire wall had previous water damage from a broken pipe…I’m like wtf? Why wouldn’t you tell us that when we were installing. Anyway, no one got hurt and the broken speakers didn’t come out of my paycheck so we just reinstalled them and anchored them with safety chains to studs.

brb I need to check my dictionary for the definition of “fun”! That is a terrifying story., exactly what I’m worried about. Good to hear joist screws should be fine.

Basics of flying anything 

first all load rated hardware, you need to make sure you use hardware rated for at least 5 times the actual load, but 7x is better, make sure that rating is for the angle the load will actually be at. Each part should be rated at the full weight including that of hardware not based distributing the load.
2. Use forged closed eye bolts not open eye bolts. Any eye bolts should be secured with washers and nuts not wood screw threads. As far as attachment to ceilings don’t attach directly to beams, either attach to a block between 2 beams with the screws into the side of the beam not up and down. This distributes load between 2 beams and the load isn’t hanging being supported by the heads of a couple of screws.

there used to be a basic handbook for flying speakers on line, if you can find it same principles apply.

If you are in doubt of your skills / math, contact your local SR provider with a flying rig or theatrical lighting company and see if you can hire their rigger.

Circ De Sole has been doing rehearsals for the past month for their x-mas show just down the street, who is the most important person involved with the show?

The rigger, they screw up people die.

Unfortunately you are going to have to cut into that drywall! But most of your repair work should be hidden by the cloud.