The way I balance the pod (schmachers) is to first setup my hubs, spur and pinion. Then with the pod removed use two gram food scales. I prefer to use setup wheels and not normal wheels but it shouldn't make much difference. Then space the motor if the pinion side is heavy or add weight to the pinion side if it's light. You can stick weights on or screw them on here or there. If the pinion side is a couple grams light I just compensate by looping the motor wires to that side. If you have a balanced pod you can straighten the motor wire run to add less weight. You have to use TLAR for that last portion.

I use the same method for balancing the actual car as well. I'll first balance it without the pod then assemble then balance the whole car again using two food scales and a balance post on one of the center holes.

In general the car drives better with a good mass balance because when you check tweak it is actually "attempting" to cross weight the car.