For the 3 Season I have only used them down to high 30's as that has been the coldest it has gotten when I have been able to get out and hang with them.
What I need to do is take the 3S and new 4S out on a real cold night and set up both but have the 4S pushed off to side and see how low I can go with the 3S and if I find out I have gone too low I can then push the 3S off the the side and deploy the 4S
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