It takes awhile to get used to the right amount of spray, I think most people start out with way too much. I try and be about 12" above the fabric, or basically one forearm high and spray lightly. You do want to be ready to quilt within a couple of days of putting it together, it doesn't last forever. You can adjust the fabric as you put it down, simply lift and move if needed.
I used cheap flannel covered vinyl tablecloths to protect my floors/table/bed (whatever I laid out the quilt on), give yourself plenty of room for overspray. Buy them from the dollar store. We have several reptiles (as well as dogs and cats) and I always opened doors/windows when I sprayed.
When I started and used too much spray, it took about 2 weeks for it to mostly dissolve. Yes, it gummed up my needle and stuck threads to the outside even after washing. Now I'm pretty good after about 3 days. I had to put in some time between getting done and giving the quilts because of this, especially for baby quilts.