Have you tried buffing the surface with a steel brush attachment in a drill between Hub/wheel bearing and inside disc, then outside surface of disc where studs poke through, then inside surface of wheel that sits against disc. If all these surfaces are free of any uneven interference the wobble should go, if not you can wheel balance all day and still have a vibration at high speed.
As far as balancing tyres ask for your rims to be statically balanced to 0 then put the tyre on and put back on the balancer again to find the heavy spot in the tyre and mark the spot, after this stage oppose the mark on the tire to weight on the rim and remove the weight then dynamically balance tyre on rim as per normal, this will reduce weight needed and make the rim and wheel much more harmonious and stay in balance longer. This is particularly good for mud tyres which are notoriously hard to balance. any tyre fitter worth his salt should know this. Hope this made sense and is helpful.