Boots are such a personal item as far as "proper" fit for mountaineering.
If you live somewhere that you have access to try in several high end boots I would suggest that first and foremost.
If that's not an option, call the company itself and very knowledgeable dealer and discuss sizing, intended use, and if you are able try them in a treadmill if your ordering online or over phone. At least that way if they are not suitable then you can return / swap.
My favourites are crispi birksdal sf, scarps rebel series, and meindl glockner gtx. These are all
High end boots and would be completely suitable, however outside of reliable construction and an appropriate type of boot, my recommendation means nothing if they don't work for your feet.
Best of luck