Auggh. I wouldn't use anchors on the ceiling, even really high quality anchors installed perfectly. If the joists aren't in the right place then run a nicely finished piece of wood between the joists and hang the QS8 from the wood.
>>or is drywall strong enough to take both the static and dynamic loads?
I should also offer the non-engineer's view (not mine, but I had to learn it over the years) -- if it takes more time to work out the loads than it does to patch the drywall, just hang 'em from the drywall and don't stand under them for a few days until you know if they're going to fall down
