Quote Originally Posted by jayvo86 View Post
Your flash power is going to be dependent on your aperture, iso, and subject to camera distance.
Subject-to-camera distance is irrelevant, it's flash-to-subject distance that matters for metering.

If you don't have a flashmeter but do have a DSLR, you can preview iteratively with that to get your exposure correct, then transfer the settings to your film camera to get a good exposure. After a while, you'll get a feel for how powerful the flash is and know what sort of aperture you can achieve with standard ceiling heights and bouncing.