Yeah, I would probably describe it at a rotation issue.
I'll try 3 in the rear. In the past my chassis has performed best on no split 7/7.
I'll post a full setup on the Xray forum later today. Running on a multi traction track sucks.
Oh well, such is life.
going lower in the rear will give you more rear traction. You want to go thicker to help it rotate (but theres a sweet spot)