For Princeton you need passing amongst all positions, most notably yes your PG (Point Guards affect passing the most in any tactic as per Game Engine PG's main responsibility is setting the offense up) but underratedly your big men PF/C also need a considerable amount of passing in order for the offense to operate. If you want to maximize the Princeton Offense, grabbing a center with some passing and guards/wings with Range will be optimal. If you want to maximize your Guards's strongest attritbutes which you say is passing, finding a scorer to complement them would bring you a good amount of success and then orchestrating an offensive tactic around that player.
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