THIS is where home rolling film, to take a bracket for over development
a bracket for underdevelopment
and a bracket for normal development would come in handy !
nice detective work bill !
maybe the facT that print compensation with a harder grade filter or paper
or developer strength compensates for the underdevelopment boosts the grainy-ness
of the final product ...
too bad you don't stick a sheet of paper ( small sheet ! )
in your camera,
rate it for iso 6 or 12 or 24 depending on the paper and kind of light
and then take that paper negative, and put it on a skillet
with a sheet of paper towel, face down, and wax it with parafin or beeswax or ?
to make it translucent-er, and then ... enlarge it ... you might get nice grain ( and paper texture! )
that way as well, and waxing the paper takes about 3 minutes from start to finish ...
( or make a paper contact print internegative of your hopeful print, and contact print the final version )