Micheal,
You wear any raingear, breatheable or not, humping up and down the mountans, you are going to be wet whether it is raining or not.
When I got my first Sitka Gear, it was for a bighorn sheep hunt in Colorado. I was amazed. Never in the month I hunted did I find one single moment I was uncomfortable. This included multiple daily 2500' climbs and long sits in every weather condition you could think of. I am an engineer and I enjoy testing things and figuring out how they work. I purposely kept adding layers on my climbs. I would POUR out sweat, yet I would not be overheated or uncomfortable and after 5-10 minutes into my spotting session, everything would be back to normal and I could sit for hours behind the binocs. Another thing that impressed me and applies directly to elk hunting was 5 minutes or so into my climb, the pants that were completely soaked from my walk thru the meadow were dry.
Sitka pulls moisture off you and keeps you comfy. Another interesting example for you. A couple years ago I was hunting in southern Ohio Thanksgiving week. I had quite a hike thru some hilly country to get to my stand. I decided to wear all my gear rather than pack the insulation (Kelvin) and outer layer (Stratus) like usual. I put my BlackBerry in the OUTSIDE upper pocket of my windproof jacket. It was soaked and I had to get a new one, yet on the inside 10 minutes after I got set into the stand I had to hang from zero, I was all set comfort wise and sat the entire day.
Bryce mentioned DWR coating. Same Ohio hunt. Chance of rain...nah, I won't pack my raingear. I layered under my 90% clothes and sat all day after it drizzled till noon. It works pretty good. I just did the same thing on my last night bear hunting in Manitoba. I was on stand at two and got down at 10:30...it POURED most of the eveningt and my 90% was soaked thru, BUT, I was smart enough to have my Kelvin vest on and was just fine. I can sit thru just about anything if I have a Kelvin vest or jacket on. They are the warmest/lightest piece of clothing I have ever owned.
A buddy of mine pooh poohed all my Sitka love for years. I gave him my stuff to take on a Colorado elk hunt last October. He has sold a bunch of his heavy bulky wool and has a full contingent of Sitka Gear now. He was amazed at how it performed and was buying Sitka Gear at every opportunity this winter.
I like that if it is hot out, I can hunt in my core top. It is camo and keeps you cool. I would wear my core long sleeve top all summer climbing our sledding hill or bleachers with a 40-80# pack training. Wear it under another layer and it keeps you warm.
So, what I would get as a middle of the road setup for any September elk hunt would be:
Core top and bottom
Traverse top and bottom
90% Jacket and pant
Kelvin vest
Get yourself a ponco to wear when it rains. Stop and hunker down while the cloud blows thru. If not, Stormfront light is what you want on a backpack/mountain hunt. It is not quiet like the downpour raingear, but you can shake it basically dry before you go in the tent. That brushed layer which makes the dp quiet also holds water that is not going to dry quickly. It is made for whitetail hunting where you are going to be coming to a house/cabin/motel every night and can dry it out.
You can go lighter with Ascent pieces or heavier with mountain/timberline pants and a Jetstream jacket, but you should be able to handle anything with what I listed above by mixing and matching as conditions warrant.
Like I said, most guys that don't like Sitka Gear have not used it as it was designed, as a system.
The harder the hunt is, the more you will appreciate your Sitka Gear.