I think a S could probably work on you if you have a 36 chest. I have a 38 chest and medium in most of the pieces has worked fine on me. The material is very stretchy ao the measurements really are misleading. My only issue with the thermal stuff is the length. The crewneck and the henley both came up way short on me.
Hmm, you give me hope then on the sizing in the chest, but I just looked at the measurements again and good point about the length it does seem short, maybe a medium would have been better for me in that regard. Well, if I'm lucky then it will hit a tad below my waist line. I guess time will tell. Thanks for the information, much appreciated.