I started out using felt. Somewhere, in one of the garage sale dimensions, I ended up with a couple five gallon buckets of various colors. THEN I actually tried flocking. It was sooooooo much easier to apply to rough shapes, and years in, the jewelry bandsaw boxes are still alive and well.
The foregoing aside, I, hereby, adopt, as if fully set out herein, the Duck's post.
As for color matching, oil paint is sticky for quite a while, so I use whatever is the cheapest, and it all seems to make fine flocking glue.
As long as I walk away after applying it, using it pales my attempts with felt.
The ONLY thing I do majorly different than the Duckster is, I drape cheap, lightweight painters' plastic in my sanding booth to contain what gets tossed at a project.
I was pleasantly surprised to learn the flocking stuff I used does not stick to it and it all goes right back on the container with just above zero effort.