Well I'm sure he can pop on a beanie and a coat...
No thermals don't seem to be a problem. Arie built some over the top hoods to investigate ( check his final page ) and said that he could only see a slight improvement on the Moon,
I think the issue of how much currents effect the view is dependent on a lot of variables. Is there wind if so what direction, what altitude are you looking , is the instrument cooled, what is the seeing like anyway and what clothes are you wearing etc etc.
The 12" binocular I am commissioning at the moment has no limitations- I got the best views of the moon I have ever had not that long ago, and it is very comfortable studying small globular and planetaries with 10mm eyepieces . I don't believe Binewts are limited in any tangible way. The only criticisms I hear are from people who haven't used true binocular scopes- those that have are usually rendered too speechless
