I have am doing another "honey do" chore for my wife putting in a bunch of 6" cans. I have a cutter that fits on my drill that does a good job on the 4". No joy on 6" tho.
I experimented with a box knife blade on a stick of wood with a center pivot hole into a screw in drywall anchor. That seemed to work OK for scoring the paper but as the blade got a bit deeper it was gouging out the hole (flat blade, round hole thing)
I guess there is an attachment for a rotozip but I don't have one and I am hoping she gets over this can thing soon.
Hole-saw in a cordless drill, as a rule. If you are really smart, you'll put a paper grocery bag just "above" the chuck of the drill, this catches any dust. Less time cleaning up, more time watching sport.
Iíve used a HolePro X-200 adjustable hole cutter for years. I think they have changed the model number for this cutter now, but it is an 8-inch max diameter, two-blade cutter with a nice heavy duty plastic dust shield that uses a sealed bearing assembly in the shaft hole. I use this with my cordless 18V XRP hammerdrill with the side handle installed. I upgraded it with their tungsten carbide cutters so I can use it for plaster, Hardiboard and fiber cement shingles as well. I also have the hole saw adapter arbor kit for it, so I can use the dust shield with my regular hole saws and my larger Greenlee RC light hole saws. They now sell a vacuum adapter for the dust shield for RRP work, if thatís something you do.
The Greenlee hole saws work reasonably well, but there's plenty of room for improvement.
Problem #1 for the Greenlee saws is that they come in several sizes that are very close together- it's quite easy to pick the wrong one, and make the wrong hole. Make REAL sure you have the right one.
Problem #2 is the ease with which any large hole saw binds. This can be hard on the wrists- and the head, if you're flipped off the ladder. When cutting through plywood, I've had that little 'bind' break things inside the big, fat right-angle drill. (More of a piglet than a hog!)
Problem #3 is the enormous amount of dust created as you drill. Better have someone hold a HEPA-filtered vacuum next to the saw- and a tarp under you.
Still, I cannot think of a better way. Maybe the fancy saw covers work; the cheap ones sure don't. Someone suggested cutting a basketball in half, and I just might try that; I can even add a vacuum hose port!
I can't see how to use a multi-master to make a round hole in the ceiling would be much of an improvement- though the muiti-master is the cat's meow for rectangular holes in walls.
As for the Ideal cutter ... when they say 'drywall' they're only kidding. Even with ceiling tile, it's one heck of a dust maker. Using the plastic packing as your dust collector, as they instruct you, is some marketing guy's wet dream. The most I would use that for would be to mark the ceiling for guiding another tool- like a saber saw or rotozip.
As for the rotozip .... here's a hint: Don't use Rotozip bits! Instead, go to a machine shop supply house and get solid carbide milling cutters that are designed to throw the chips / dust DOWN, away from you. These will push a large amount of the dust into the wall cavity, rather than filling the air around you. Expensive, but worth trying.