Nice, David. Looking good. Lots going on in your vid. Tire balance on bigger off-roads is pretty much a check out. What it is is what you get.
Try spin testing both tires at the same time. This will give you an indication if one or the other tire/wheel/bearing is causing drag to one side or the other. Not so much a big thing in bashing, but in racing another one of those 'little things' that matter. Usually either slightly loosening or tightening wheel nuts will even out rotation time bring them to a stop pretty close to the same time. Then double check end play to ensure its gotten neither too loose or too tight.
Something I picked up on RC drag racing back in the day. Anything that helps the car go a bit straighter is always a good thing. Keep up the good work and good posts. Cheers. -AC