As alternative you could try balancing bags in the tire. We used them in many semi’s when we ran service calls out on the road. They seem to work well although I’m old school when it comes balancing. There are two planes when it comes to balancing, first is static which takes most of the up and down movement (layman terms) out of the tire. The other is dynamic which addresses the side to side movement, usually you can tell as wheel weights are hung on both side of the wheel flange.
If you rotated the tire 180° on the wheel and the balance didn’t change much (1oz) then I would have dismounted the tire and checked the wheel runout a long with the balance. Not real often, but I have found wheels are the culprit in the wheel/tire assembly taking too much weight. However in this instance where you state the tire is cupped it may be next to impossible to real get the tire back into a reasonable balance.
The one one alternative is to take the tire/wheel assembly to a commercial tire dealer that has a retread plant. They can send the tire into their retread plant and round the tire. Yes you lose some rubber, but they just take off the high spots. We used to due that quite often when the driver had to lock up panic stop especially on new tires or new retreads. We even took out the ground down section and replaced it with a new section of rubber, then after curing we would send it back across the buffer to round the tire.
Oh, just so I’m transparent, I’m not totally against centramatics, just not a huge fan. I’ve seen them “lockup” creating the problem you originally were trying to solve.
We will all miss him, our Prayers go out to Candy and the rest of the family. He is probably up there now installing motion light in heaven.
