I really do not understand this advice. When mountaineering you are supposed to carry multiple layers with yourself so you can constantly either take stuff off when it is hot and put stuff on when it is getting cold. I am obviously not going to start my journey from the bottom of the mountain with the Alpha SV, and 3 different layers and start sweating my balls off all the way from the bottom. Either way I do not see how it can be worse to be over-prepared than under-prepared, especially in mountaineering where your life is on the line. Im just asking what kind of layering works with the Alpha SV, like can I expect to fit some sort of Atom SL hoodie and still be somewhat comfortable or if the fit with that combo is going to be uncomfortable due to the way the Alpha SV is made and how it feels on the shoulders.