^ Looks good.
I didn't know 3M made Super 90. I've seen Super 77 and Super 77+.
Back when I worked at a car stereo shop, we use contact cement (the stuff you use to glue down laminate (formica countertops)) thinned out with lacquar thinner and shoot it with a spray gun.
A plastic putty knife would also work for tucking the edge of the fabric behind the panels. Becareful if your using it around vinyl though, you could scratch, poke a hole in, or rip the vinyl.
Thats why the best way to do it, is to remove whatever piece your covering (if it can be removed). This way you can wrap the fabric around the backside of the panel and glue it down.