Can I lend a bit of advice here?
Thin layers is the way to go in my opinion. You need an outer shell that is windproof and traps air.
I used a double skinned canvas parka some of the time, not unlike some of the jackets that TwoDogs makes, and occasionally some Ventile over trousers if really needed.
I rarely needed them when I was working or on the move.
Below that I had a mid layer of wool.
This consisted of a thin wool sweater, a medium weight wool shirt and a thicker wool jumper worn in any combination according to need for my upper body and a medium weight pair of wool trousers for my legs.
My base layer starts with a merino wool long sleeved top and leggings next to the skin. The leggings I use are Woolpower® 400g.
I carry a spare base layer of thinner merino which can replace these if conditions are mild or can be added underneath for more warmth if needed.
It also means I have a dry base layer in my pack if I should I get wet for some reason.
The important thing is to operate at just the right temperature, the Goldilocks Zone, not too cold and not too hot.
If you overheat you will dump moisture into your insulation which affects its efficiency. The problem with thick warm coats is that they are an on/off solution, usually far too warm to work with on and you are too cold without it if not working.
My Goldilocks Zone is about the temperature that you feel in the chiller isle of a supermarket when you are wearing a tee shirt. At that temperature I am not going to start chilling but I won't sweat like a beast if I start chopping some wood or dragging a sled.
If I'm going to be stationary I will add another layer for comfort, if I'm about to start moving I will dump a layer in preparation. Always dress for what you are about to do.
Thinner, multiple layers allows you to fine tune the combination to a perfect degree. Thick "Mothership" type solutions are much less flexible.
Just my opinion...