Thanks for the informative answers. Although I do like GT1M and Checkmates answers, I'm gonna err on the side of safety and follow the 16 hr rule of thumb that Rickmerrill, Georgesalmon, and WOG suggest.
Hmmmmm, ok, so it looks like I wasted a lot of time by grinding, scuffing everything at once, I should have just waited till I was ready to work on each area, at least as far as tying into the original glass on the boat goes. My reasons for grinding all at once were to get it all over with, and to avoid multiple clean ups. Oh well, live and learn. At least scuffing what has already been grinded (ground?) should be easier, just a light touch up I guess. And I will wipe everything down with acetone after vacuuming, I gotta think removing the fine dust is a good thing.
This brings me to another question.........how long should you let the acetone dry before laying up fiberglass? Does it even matter?