I have 1 1/32" thick washer under the left side of the motor mount on mine and it seems about right. You still need to hold some right rudder on and after takeoff til the speed builds up, but it pulls pretty straight in the verticals.
The test for side thrust I was taught was to pull vertical and watch. If it diverges to one side or the other right away, it's aerodynamic; if it goes straight for a while, then pulls to one side or another after some of the speed comes off, it's sidethrust.