So far this is the DIY project I dislike the most. Removing tons of loose styrofoam from my attic. Only doing part of it for now to get access above a bathroom that we're remodeling. Eventually I'll remove all of it, seal the air gaps, and probably replace the insulation with blown in cellulose.
The the insulation vacuum bags definitely make it easier.
What is up with that vaccum? I am needing to do something similar and was going to lug a 21 gallon shopvac into the attic with an extension cord but your solution looks much more efficient.