I have used the 505 spray for years, for emb. I use the 505 in the red and tan can, it is temporary spray.
Now I made a tube out of card stock to fit onside of the hoop and then spray inside the hooped backing to keep from spraying my hoop.
Then I place my garment inside the hooped area and sew. You can also un-hoop your sprayed backing and place your garment over the sprayed area and re-hoop. I have not had a transfer of spray on to the garment and my hoop stays clean and not sticky.