Nicholas, Thank you! What I think I'm going to do is to invest a few rolls of 35mm Forte 100 and try the methods above. That shouldget me in the ballpark. And waiting for more fog around here (we don't have winter anymore) isn't a big problem.
Actually, what I shot was a group of fairly high-contrast scenes; dark cedars against snow and fog.
I was thinking about P'Cat HD (it's already mixed and does a great job with APX100) because Gordon Hutchings (I think) mentions that fog comes out well in PMK and I thought P'Cat HD would be as close as I could get to PMK.
Hey, I'm open to anything...