Trying to color match gray trim with vinyl die

I scratched up the cargo area of my Prius v (lowercase v for the Prius v wagon) pretty thoroughly, with several gouges and scratches that affect 3-4 different panels. I would like to repair it. From YouTube, it looks like one can do so by:

1. Sanding the area with 220 sandpaper
2. Filling the scratches/gouges with superglue or various types of vinyl filler
3. Sanding again until smooth
4. Spray painting the area

There are enough of these that spray painting appears to be warranted; the video I watched said to use "Vinyl Die".

I have two questions:

1. Does this seem like the best approach to fix the problem?
2. My trim color code is LA18. I have had NO luck trying to search for vinyl die with this trim color code. Any ideas on how to find such?