Porta VC 400 or 800?

or something else completely? I'll be travelling to Yellowstone and
Southern Utah this summer, carrying an old Olympus 6x6 folding camera.
It has a red window in the back for the film counter, with a sliding
cover (I don't know if any of that makes a difference when using fast
film in an old camera.) I want to use fast film so I can use small
apertures. If I get any spectactular shots, I'd like to be able to blow
them up to 16x20 without getting too grainy. Most of the good pictures
are destined to be 8x10's.

I'll also have some Kodak Gold 100 film or equivalent with me for full
sun situations.

Thanks.

Best regards,
Bob