Thanks, Joel, Doug, Steve, and the rest,
I can see that for any of the dry media put inside the tires that Michelin is very concerned about humidity/moisture levels within the tire. My guess is that clumping or sticking of the material within the tire would enhance the out of balance characteristics and add damage to the tire structure over time.
The only way I could meet and maintain the low level of 3% moisture level would be to only add air in the desert or use nitrogen with the beads and that posses its own issues of not being able to maintain your own pressure levels. Here along the gulf it is most always humid and even with my moisture separator on my compressor I could never get near that spec. Under varying conditions, moisture within the tire will condense. For me, given where I live, internal media is probably out of the equation.
Doug, do you have a link or a name for the external units that you use and how do they attach? Still leaning towards just getting the fronts spin balanced but I will look at external units and see what the pros and cons are and how effective they are.
The comment about tires moving on the rim with use is likely true but if it is minimal, that is a few degrees of change, then it does not matter. If it is 45 degrees of 360 degrees over the life of the tire that is a factor. I have no idea if this is just an anecdotal observation or a real issue. If it is a significant factor it would lead you to some kind of dynamic compensating system, if one exists, that is not problematic.
Later Ed