I think you should get the right color seat covers.
Having said that,
When I first got my WH Procar Rally2000 front buckets I wanted the original rear parchment seat to match so I used the vinyl/plastic Colorbond paint.
I didnt expect much, but I was amazed at how good it looked for the ten years I ran it that way.
Still would sell what you have and get the right seat covers but look at the attached photo. That seat got climbed all over by little kids and dogs and never looked like it was painted/dyed.