That stepping back ten feet thing is basically what animators do with their work flipped.

Did you sand the edges after heating? That's where cheap mats usually bite you, the seams crack if you don't feather them down smooth. Harbor Freight mats have a weird grain to them too, so I hit mine with a light coat of Plasti Dip before painting and it kept the texture from soaking up all my spray. Mine lasted two full con weekends plus a Halloween party, no real damage except some scuffing on the belt area. Just watch the heat gun on the thin spots or it bubbles up on you.

Watched my friend do the same thing for an hour and clear 12.