It also turns out to be photography which sells.
Pouring buckets or harder makes the images all the more attractive.
Vertical format = has a narrower footprint on a wall. I print all my own to 16x20
Unusual shape = I sold a lot of 6" x 20" rain prints (real silver, analog prints.) $40 each.
NO PEOPLE! The psychology is that the viewer wants to be the "first in" to fantasize about the scene.
Try to shoot a range of shutter speeds to get some action out of the rain +/- wind.
I'd put a 6x9cm back (8 shots/120 roll) on a 4x5 Graflex SuperGraphic, rug up and go for a stroll.
Even 4x5 sheet, Ilford D400 was the very best, soup in Kodak D76.