All these EI settings claimed by anyone here are more or less meaningless without the metering method. If you meter the shadow area, you can easily underexpose by 3 stops from metered and get pitch perfect results.
The one relevant fact is always: if you meter one region, you will some image detail in areas 4 stops darker, and close to nothing in yet darker areas. If you pushed a long toed film really hard (think: HP5+ in Rodinal stand), you could get away with 5 or 6 stops, but with modern short toed films you are stuck with that 4 stop limit.
If you are unsure, meter some uniform area, then search for areas which are darker. Down to 1/16 of that brightness will work, and below that will not show details pretty much regardless of how you develop. Preflashing can
help, but it's a lot of hassle, more than many here are willing to accept.