The last quilt I spray basted was large (65 x 90+) and I used this system which was posted here in another thread about spray basting
https://www.youtube.com/watch?v=XPaI...ature=youtu.be It saves you having to crawl around on the floor. The room with my big cutting table has carpet so I did put sheets down over the carpet. It worked very well.
I use 505 spray.