In theory you could plot out a scale drawing using the film frame dimensions and distance from film to pinhole, aperture, etc. But in fact, it can be pretty challenging to get accurate measurements. The film/frame diagonal defines the minimum circle of coverage to avoid vignetting. Drawing a pair of lines from each end of the diagonal and crossing at the pinhole lays out the limits. Then the issue is plotting in any other "stuff" accurately to see if it encroaches on those lines. It's probably easier to load cut pieces of film and make test exposures.


(Some day I may learn to use this CAD package ....)

The numbers there are extremely loose guesses based on general 6x6 format and your comments.