I would go with Mike Sigel, Earl Strickland, Johnny Archer, Effren Reyes. Constant success over many years. I'm sorry more footage of Willie Mosconi does not exist and I've read that Luther Lassiter was a sick 9-Ball player.
That would be Willie Hoppe who was an exceptionally good pocket billiards player (on 5' x 10' tables) and more importantly, the greatest 3 cushion billiard player that ever played the game.