I have never used spray baste -- what does it do? I am assuming it must be something like photo spray glue. Does it hold everything together without pins or anything? You must have to do it on both sides of the batt so both back and front will be smoth.
I would think if it holds that well, it must leave a coating in the quilt?
I think I must have been out of the room when the whole topic of spray came up -- We have so many allergies in the family --even to dryer sheets, that I hesitate to add anything I am not sure of.