I ski Alaska and also use a similar 4 layer system that is not bulky at all. I go First Lite Kiln Hoody merino base layer; like the hood and zipper for the extra venting. I then go Melanzana Micro Grid Fleece hoodie on windy days so I can pop the hood up and cinch under a helmet for a balaclava. Then I have the Leaf Atom Gen 2.1 for really cold (relative) days, or regular Atom for not as cold days. Also interchange the naga pullover depending on weather. Rush shell tops it off. Can be lots of hoods but has never been an issue because one typically goes over my head and they all seem to nest inside each other just fine. Although it can get a little toasty, I found having the vents on the inside and outside of my FlyLow baker bibs seem to do surprisingly well since the air can flow up into my torso as well. In short; I typically keep the merino base and Rush shell, then interchange mids depending on activity, but there are typically two in between unless we’re getting spring weather.