I got myself the knee pads from the dollar store for crawling on the floor. I would rather crawl then lean over a table which makes my back ache.
I have sandwiched on the back of my garage door when using 505 basting spray and it worked well. I tacked up a fabric strip to the wood above the door first. I then pinned my backing onto the strip. I sprayed the back and smoothed on the batt. Sprayed the batt and smoothed on the top. When I had it just the way I wanted it, I removed the pins holding the whole sandwich to the scrap strip on the door header. I didn't have to worry about any over spray or fumes because it was the garage.