FWIW, I do a lot of night work with different B/W films, and the films have different LIRF, but in practice, the supplied charts usually work fine (for me)... I meter so that the darkest part of the scene that I want start to render is 3 stops under zone V, to have some detail is 2 stops under V, and full detail 1 stop...

The long exposure time covers up most of the minor differences allowing some "fudge factor", so not a problem...

What's annoying to me now is the only sheet film I can afford these days is (Foma) EDU100, and not unusual for an 8 min (or much) longer exposure (a still life I was doing was properly exposed in an hour!!!), so sit back, and get comfortable...

Steve K