I have a North Star, James.
It will be warm enough for the temps you want it for, but it’s not a super warm down jacket, i’d put it more in the wearing-at night- when-moving-fast-in-the-alps category than sitting-by-the-campfire type jacket. You’ll notice the difference in weight and fit compared to other common down jackets (much slimmer profile). Looks good on and you don’t look like a michelin man wearing it to the pub.
I love mine, it’s worn all year round, most weekends for everything from packing the car to draping over my sleeping bag when i’m cold on a summit camp in the middle of winter. Packs down small and has a good length (much better length than most i tried). Hood is excellent and the fit is really good.
Sitting around, I’ll wear it down to about -3 or 4 with just a t shirt, then i’d look to stick on another layer.