In my (admittedly limited) experience, if you black vinyl-spray over the blue it's imperceptible for years. Might be tempting to do both sides so the lustre matches. Black is of course preferable.
Doing it over the tan isn't so successful, as it only coats & doesn't soak in, being in a "high-traffic" location you eventually scrape it off with a fingernail or a knee ... same with the blue, but it's much harder to notice.