I would use one of the suggested products AS DIRECTED. If some remains, do the "custom dyed" number, although in our show, the judges do not see the histories and would not see that. I went back and see that you redid it. Good for you. Maybe try again, as well.
I began with an attitude of avoiding prewashing. Now I prewash everything. When in doubt, put a scrap in warm sudsy water, slosh it around and leave it for 15 mins. Reds and blacks are the worst.