Riveted seat track guides onto seat frames. Installed seats and sat in my plane for the 1st time since starting the build almost 3 years ago! Very big day for sure. Started aileron balancing process. Used 1" ID PVC pipe to measure how tall a column of 3# 4oz of lead shot works out. It was just over 15 inches. Converted to 1 1/8" ID aileron spar, that works out to just over 13". I used this measurement to know where to spray the internal plug of expanding foam. I put it at about 20" from the inboard end of the aileron spar to give a lot of leeway when inserting the lead shot and epoxy slurry tomorrow. Will let the foam dry overnight in 70 degree temp as others have recommended. Thanks to SIMDPK and others for the initial 3# 4oz weight for the lead shot. I'll confirm this tomorrow by first balancing the aileron with dry shot, empty it and then will mix up the epoxy slurry for final balancing.