Since some people people have found this useful I'm posting an update. Six months have passed and I'm very happy with the results. The nodes using the 4 second sleep are barely now into the nominal voltage of two AA batteries (3V) and I think those can last a copule of years like that. The 2 second sleep node is dipping a lot faster, but I suspect that the cause is the Si7021 taking readings every 3minutes that is accelerating the decline, even then I think this one could almost make it to a year.