[drc]

To establish for buyers that a reputable outside source says the signature is genuine would be to consign one to a reputable auction house. When they offer and sell it, you would then have evidence for buyers that a well known and reputable place has offered it as authentic. If a place like Lelands offers one as authentic, that would help your cause. Even if you already had PSA/DNA letters, saying a poster from the series was once auctioned by Lelands (or whomever) is good marketing. Potential buyers like to hear stuff like that.

Of course, if they are genuine, you could consign them all too.

Duly note that I'm not an Ali signature expert, and am not offering an opinion on the signature.