From my experience it seems it works better if you have a helper to help layer everything smoothly.
When I used it the first time, I thought I was doing such a good job of keeping everything straight and flat. I taped the corners of the backing.
I placed the batting on carefully smoothing out any lumps and wrinkles and then gently rolled the flimsy on top...spraying each layer lightly being careful not to overspray...
I turned that puppy over the check and it was as bad as when I safety pinned.
I was so disgusted because the adhesive held really well and I had to pull all the layers apart and start all over.
I waited until I had a friend over the help hold things tight.
Then I tried Aquanet hairspray. Only because I've heard people talking about it. And it's cheap. So I tried it on a scrappy top I had laying around. My exerpience is I have to spray heavier then the adhesive spray, best to do it in a well ventilated area or you choke on the fumes, and let it dry completely before moving. I'm not sure I'd use it on heirloom type quilts but for my utility type quilts-love and use until it's rags it's fine.
I keep alcholol wipes near my computer and wipe the needle when ever it feels like it's gumming up.