I never put a quilt on the floor to sandwich it, even a King size.. You won't believe this but I used a Queen size bed and sandwich all my quilts on it... I just make sure the back is ironed and smooth and the batting ( I use all cotton and put the dimple side up to better grab the top) I also smooth the top really well before Pinning it...
I have spray basted some using 505 but most times I just pin and not a whole lot of pins.. I also quilt on my lap and with no frame...
Haven't had any problems and have been quilting since 1985..
Hugs
Ladybug