HAH !
This reminds me of episode #16 in fantastic norwegian series "Don't do this at home!"
en.wikipedia.org
They wrapped a caravan in plastic and managed to collapse it with just regular vacum cleaner.
Before that they had hauled in a carcass of a dear or like and studying how fast the flys multiply - horror - horror.
But yeas - vacum has power if you can address it correctly.
Nuuska,
I wasn't planning on trying to collapse an entire Music Store, or Rhinoceros, but merely apply enough atmospheric pressure to an area just slightly larger than the bridge plate on top of the sound box to keep the bridge in place until the glue sets.
However, your post does bring up an important point, which is, how do I brace the interior of the sound box to ensure that the atmospheric pressure doesn't cause it to collapse?
Since the sound hole is too small for me to put my hand inside, I likely won't be able to easily get a wood brace inside, so I was thinking a tennis ball might work.
Glue or duct tape a shoelace to it. Force it in with a screwdriver or some such, and afterwards, pull it back, and if necessary puncture it to allow it to be slightly deflated, and more easily removed.
This project is becoming more and more interesting, and the parts aren't even out of the box yet!
Good stuff.
RBSinTo