Now in your case, (for now) I think I'd try simply adding 2 more ounces through the stem....Your beads have simply reached the limit of their ability to balance. (Who the hell goes 85 in a mudder?
My top speed is 74).
As I recall from my youth, 1 ounce creates 60lbs of pull/force at 60 mph.
I could not find anyone to balance my tires successfully either. Our trucks live in a no-mans land between automotive and commercial trucks. The auto shops don't have 42mm sockets. The commercial guys don't have accurate machines and no one has a lug-centric adapter. There is one device that would work, an on-the-vehicle balancer by Hunter or Bee Line but these haven't been made since the 60's..........I know of 2 in my state. Neither are used regularly at the shops where they live.
I think once everyone tears down and spins each rim to determine the weight required to balance (or correct deficiency) and adds that to the bead weight from the chart for the given tire (plus maybe an oz or two for missing chunks) they'll be happy.
......and then the government will outlaw the beads due to some environmental concern.....