Atom heavyweight or thorium.

I am super confused . I am looking for a stand alone jacket for temps in the -5 to -15 Toronto weather . I want the thorium as it seems to be the warmer option but I like the atom heavyweight for wetter conditions . I tried the thorium with a shell and it's way too bulky for me . The atom with a shell seem fine but just not sure if it's going to be warm enough . Any help is appreciated as I don't want to buy 2 jackets