Quick update on the TireBalls I put in a while back. Today I decided an inspection was in order, so I pulled the rear wheel off and removed the tire. After 2 races and 3 or 4 regular rides, all the individual cells were still completely intact, and no mud or grit had entered through the old valve stem and 2nd rim lock holes. I had previously filled those with RTV sealant before taping over the spokes. Good to see it has kept the mud out.
They had lost a little bit of pressure, so I went ahead and topped them off and put the tire back. In the process, I was able to squeeze one more cell into the rear tire. My confidence in these is growing. It's great not having to worry about flats. So far so good.