Read all the responses and I apparently do things a bit different.
I like your FL Aerowool - Sitka Core Heavyweight layers - ALOT. I use the exact same setup. Unless its really cold and/or wind is blowing, I hike in like that. You'll discover temps in the west don't feel as cold as comparable temps in the east thanks to alot less humidity in the west. I promise you won't freeze to death.
As to insulation, I tend to run with a puffy of some sort. I have several weights of puffy jackets from very lightweight to really friggin' heavy (Sitka Kelvin Down hoody). I use the puffy: when its cold, I wear it hiking, or when the wind is blowing such that I'm getting chilled just hiking. Hence the different weights. My goal is to arrive warm but not sweaty. I manipulate clothing accordingly. I've hiked in with just the Aerowool top on. My goal is not get all sweaty.
As to an outer shell, I wear one when I'm stationary, mostly to cut the wind. I need a hood at a minimum on my outer shell. I love hoods, a jacket without a hood isn't worth much to me. Others dislike hoods. When I arrive at my location, I normally don the puffy and outer shell.
Example - this past year it was 0 degrees the first day of Wyoming elk season with a 5-10 mph wind. I hiked in the dark with both Sitka lightweight and heavyweight bottoms, Aerowool top, Sitka Core Heavyweight hoody, Sitka Timberline pants, smartwool socks, Crispi 400 gr boots. I had light gloves and an orange ball cap. I was hot when I arrived 2+ miles later at my starting point. I cooled down waiting for light to come and put the Jetstream on. I still hunted all AM in that setup and was a bit warm. At lunch, I took a "stand" (aka napping spot) in a smallish meadow overlooking a small saddle. Elk tracks indicated it was a good spot. I put on a Sitka Kelvin Lite Hoody and Sitka Jetstream. And proceeded to nap in the sunlight and temps ~ 15 degrees for an hour. (as an aside, never underestimate the power of a mid-day nap in elk season <G>)
I've worn an assortment of Cabelas, Bass Pro, Gander Mountain, Patagonia, Kuiu, and Sitka products. I'm sold on Sitka. They do what they say they'll do. They are pricey but most good equipment is.
