Winter kilting in Pacific Northwest?

[knotty]

I live in the Cowichan Valley 20 minuted north of Victoria. I have been wearing nothing but kilts since mid February. I have been warm enough in my 13 oz. 8 yard on the few cool days we have had. I would like to continue my kilt adventure through the winter.
I am planning to get a 16 oz, specially for winter. Is there a preferred style (8 yard, 5 yard, box pleat) for staying warm in winter?

Craig