If you play him at SF, set him at 0. If you play him at guard, set him at -1 until he hits 70+, then go to 0. If he can get to 75, set him to +1.
You barely shoot any 3s, so you should see a lot of - defense. Even with him set at 0, he'll shoot a decent amount of 3s at 0.
If you play him at guard, set your other SF (who is currently at 64 per) to 0.
I have noticed a bit of a different per scale depending on position.
For guards, per needs to be 70+ at D3 as a general rule of thumb to be very effecient.
For SF position, 60+ will usually get you decent effeciency at 0 setting.
For LP, 50+ can get you decent effeciency at -1 or 0. If you get a lp player 60 or higher with some handle and speed/ath, then 0 generally works very well assuming you aren't playing alot of + defenses