As promised, here are the results of my test of the CR123a batteries removed from both transmitters using the ZTS multi-battery tester (see attached image). This device has two patents related to pulse loading the battery which simulates an appropriate load. It has a 5 LED scale. Each light signifies 20% capacity.
The battery taken from the ISS came back with all 5 lights lit which means, essentially, it was full. Of course it may have been somewhere between 80% and 100%, and still lit all 5 lights. On my digital multimeter it read 3.02V. This was higher than the initial reading 20 minutes after removal (2.98V). That's probably because the internal portion of the battery was still cold at that time and subsequently warmed.
The 2nd battery which was removed from the wind transmitter came back at 80% or 4 out of 5 lights. However, it too tested at 3.02V on my multi-meter. 15 minutes after removal, though, it was at 2.92V.
Either way, I'm guessing that in extreme cold the OEM batteries have to be, essentially, full strength or there will be issues when the output drops with temperature. The SureFire replacement batteries claim to operate at lower temps (-76 vs -30). Indeed, ValentineWeather has used them in temps well below zero and had no issues.
Since installing the new batteries, I certainly have had fewer dropouts with the ISS (only one so far that lasted the better part of an hour before I caught it and put console in setup). Ironically, the wind transmitter, which had the weakest battery, has not improved. I'm seeing regular dropouts on a ~5hr interval lasting anywhere from 10 minutes (most common) to half an hour or longer. It does make sense that the anemometer battery would be drained faster because that transmitter is having to do calculations every couple seconds.
Anyway, the new Vue console should be here late next week and I will post back once it's had time to establish a track record. In the meantime, if you have anything to add to the thread that will enlighten those of us who experience signal dropouts in cold weather, please do! Thanks for reading and/or contributing!