You think Spinks' wins over Tangstad and Cooney prepare him to beat Tua? I don't see how Spinks of the bad knees stays away from tua's power for 36 mins.
Go watch 10 minutes of Tua, guys...a round each from 3 fights or something. If a guy is moving Tua does not throw anything except tentative jabs or little range finding 'crab touches'. Without his feet set under him for a good couple seconds (usually when a guy starts getting tired and hanging around against the ropes), he's no threat at all. Spinks would win this 12-0 and look like a heavyweight legend.