I am looking for some advice on changing my ice climbing approach layering system this upcoming winter. Temperature can vary greatly, but anywhere from -10F to 15F is relatively common before the sun has risen when making long approaches. My main problem tends to be how much I sweat as I find myself hot easily.

I usually wear patagonia cap air base layers for top/bottom. While not ultralight, I wear rab alpine ascendor pants for my outer pants as they function well for what i desire when climbing. While my legs do sweat some, it's mainly my top. Even wearing nothing but the cap air, I usually tend to get so sweaty that when I eventually stop moving I get cold. Especially my back from where my pack sits. A common approach on longer days may be in the realm of 5-6 miles with 2500ft of elevation gain. Last season I was just bringing a spare base layer top to change into, but it would be nice to avoid that if possible. Especially for multi-day backcountry trips.

I've seen people discussing the finetrack mesh and bryjne mesh as a layer to wear under the baselayer. Would something like that help to prevent getting quite as cold even if I get quite sweaty? Would alpha possibly make a better option as a baselayer over the cap air? I usually avoid other layers over top of the cap air when approaching as I tend to wet out those layers and then find them cold to wear when belaying. I tend to bring a proton lt as a midlayer/outer layer depending on temp and conditions, a gamma lt soft shell and then usually a big belay puffy as my extra layers.

Also considering possibly replacing the proton lt with another midlayer. Would alpha be the best bang for the buck for that? Possibly alpha with a shell attached to it or would I be better served with two separate pieces? I realize my layers could definitely be lighter but sometimes a few ounces is worth extra comfort or durability when climbing.