It seems like a lot of layering systems rely on the wind breaking features of an outer softshell. Does your method eliminate the need for that softshell? Is there an advantage for having a single purpose wind layer and how does do you think it would work for someone who sweats excessively? Would you pull it off when moving like you would other layers?
Great questions. Id like to preface my answers by saying there is no right or wrong way to these systems. Everyone has different biology, favors different aspects of gear like weight, warmth, moisture management etc. So this is my experience and it comes from years of trial and error before the information was so readily available on the interwebs or the technology was so good. Now with the caveats out of the way lol.
1. Yes a lot of layering systems do rely on a softshell for wind breaking and yes my method eliminates that need for mountain hunting.
I have a Sitka Jetstream (not the new version) for example but I never use it mountain hunting. Its used around town, at the kids sports games, and its probably my favorite jacket for pheasant hunting because it seems like its always windy and the jetstream is tough as nails for brush busting. However, it doesn't make my pack for the mountains because its heavy, doesn't pack as well, and isn't as versatile. I save weight and gain versatility by having a dedicated wind layer and a mid layer instead of a jacket that is a wind layer and mid layer in one piece. I can wear just my mid if the wind is low and Im really active, just my wind layer if its windy but not super cold and really active, or both it its windy and blustery cold.
2. How does it work if you sweat excessively? I think this is where understanding the different types of wind layers and trial and error can come in.
First let me talk about the different types. You have tight knit wind layers like the Patagonia Houdini, and you have true laminate wind layers like gore wind stopper. The tight knits, in general, are probably going to breath better than the laminates by nature. So if you sweat alot one of these might work best. The laminates are going to block wind better and are usually made into hunting specific pieces like the Sitka Mountain Jacket. So knowing your body, managing your pace (something almost no one talks about), and being honest about your hunting style goes a long way. Example one, you bow hunt elk and are moving almost all day and you sweat a lot, a knit wind layer might be best. Example two, you hunt rifle deer and your preferred method is to run ridges stopping at each exposed glassing point for extend time to pick apart the country with optics, a laminate is probably best. In example one I'm favoring breathability in example two I'm favoring wind blocking. Ill also say that if you REALLY sweat a lot then maybe a thin wind blocking vest might be the best bet instead of a full jacket with sleeves.
Now let me talk about best practice for a wind layers position in your system. In my opinion it is vital that whatever wind layer you pick, you wear it as close to your skin as possible in almost all circumstances. Here's why, whether its a knit or laminate, its never going to breath and move moisture like your base layer, your mid layer fleece, or even your puffy. So, we need to try to maximize its ability to push as much moisture through and trap the least amount. How we accomplish this is by putting this layer as close to the heat source (your body) as possible. Heat is what pushes the moisture through these garments. If instead we put it on the outside, then we cant push the moisture through as effectively so its stays in your mid layer and you just become wet, clammy, and cold when you stop. The best example Ive ever seen of this was years ago we were hunting rifle season in -10 degrees and dry. My buddy decided to wear his base, mid, puffy, and rain jacket while hiking thinking he'd be the warmest that way. When we stopped he was wet all the way through and his rain jacket had ice all over the inside. Why, because his rain jacket which breathes absolutely terrible was completely cut off from any heat from his body. So as his other layers moved the sweat efficiently from his body, the rain jacket couldn't and instead froze. This cut off all moisture movement and soaked him. The only time Id wear a wind layer on the outside is if its warm enough I dont need another layer, or there is active light precip, Im moving and I dont want a rain jacket on.
Last question is would I pull it off for moving? No. If its windy I almost never take it off. One, its inefficient to constantly be taking layers off and putting them on. Especially if they are under your mid layer as Im suggesting. Two, Im going to sweat regardless and Im going to be damp when I stop. Id rather be warm. When I stop and its cold the first thing I do is pull out the puffy and put it on and put on the beanie with windstopper in it also. This traps all the body heat Ive just generated hiking and cooks my system dry. In my experience with high quality layers, especially synthetic base layers, Im dry against my skin in less than ten minutes and Im comfortable. After that I don't care how long it takes to move through the rest of the system but when I get up to move agian and the puffy comes off, usually all my layers are dry and Im ready to roll.
This was probably way more lengthy than you wanted. Sorry I'm just trying to be thorough because wind layers are the most misunderstood, undervalued, and misused layers in my opinion. I think guys would be amazed how much more comfortable they will be when they incorporate them properly into their systems.