I think that's a good start. If that proves to be fruitless, dyeing them is the next option.
I used the adhesion promoter and dye from O'Riellys and it seems to be holding up OK. I haven't had any rub off yet, of course like yours the car doesn't get driven a whole lot.
The key to it is in the prep, clean, clean and clean. Follow up with the adhesion promoter and then several thin light coats of dye until you reach the desired coverage.
