At risk of being contentious, I'd perform some preliminary tests with a digital camera, make adjustments for reciprocity and then bracket three or four exposures on 5x4.
If I had the time, and knew the weather was going to be consistent, I'd do some tests on 35mm or MF between the digital and the 5x4.
Otherwise, try to get hold of one of the old "Kodak Data Guides for Professionals". They used to be printed in a letterbox format and were full of useful info - such as exposure guides for unusual situations. I've not referred to mine recently and I can't find it, but when I was shooting lots of film it was always a good starting point.