Can't speak for balancing beads but I have used BB's to dynamically balance 35" MTRs for about three years. Works very well except for the noise - the BBs keep spinning for a while once you come to a stop. Balance appears to be quite good and I have driven the jeep up to 120 km for short periods. This may seem low to some people, however, that's fast enough for me in an old jeep with 7" of lift. Tires have worn quite well.
Also been experimenting with antifreeze in 36" TSL Bias tires. Quieter, however could be more of a problem to cleanup if a tire comes off a rim while on a trail ride. Also can't drive as fast on these - I grit my teeth at about 80 kph.