Any time I combine a Gore XCR shell with long johns, I cook. I even have to vent the full zip at some point during a hike. I have been using Patagonia's French Roast or Guide Pants on Baker, Rainer, and Prusik Peak. Now I leave the XCR pants at home and just bring my guide pants with a rain shell. I think it boils down to personal preference mostly. Go for the Gamma pants if you can afford it.