RE: Toe in, toe out or neither ?
The most standard setup for MT's is a slight amount of toe-out at the front and toe-in at the rear. Increasing toe-in at the front should give more on throttle steering, although it may make the truck slightly harder to drive.
The steering is not an issue - when the wheels are rotating they will easily find their centre (i.e will face directly forward). It is just that when stationary the servo has insufficient torque to move them exactly to the correct point. My MT-A4 truck does this, although it is running a servo with a decent amount of torque.