Is Payne a good shooter? I don't know what advantage he gives you if you decide to go small. Isn't his best trait is that he's good at running an offense?
Payne allows you to rest Russ and run the offense through Durant when he's on the floor and Russ is gone. I'm sure he will play with Durant and Russ, but I don't think that will be one of your better lineups which is my entire point from the beginning.
A small ball longlineup will generate live ball turnovers (I include shot blocks as well). The more ball handlers that can make plays the better in that situation.
Also, when RW attacks the inital PnR the player who receives the pass has three options. Pass/Shoot/Drive. Payne can do all those things and further expose a defense.