I have recovered seats with missing foam. Find some sacrificial foam, shave it to shape with scissors whatever, glue it in the gouges...then here's the trick...cover the patches with really good tape, I've used that super sticky tape that they use to shrink wrap boats with.....then use a good aftermarket seat cover.....use a heat gun (or do it in the sunshine) to soften the new seat vinyl to manhandle it into shape. Personally I prefer a air compressor driven stapler to put it all back together. BTW: I remove the original seat cover and all staples, etc....may not be necessary but that's how I prefer to do it. It is tedious work...but fulfilling once its done.
