I know it sounds obvious, but i think there's an app for that.
You can download lightmeter apps, don't think they are very accurate, but could be a starter point, and print film is reasonably forgiving for a stop or 2 of exposure either way? Otherwise there will be tables on line for recommended exposures.
I do have a small handheld lightmeter in a leather case that I was given lying in a box somewhere, must be at least 70 years old. I could send it if it was any use? (and I could find it.....)
