When I set up my process for 4x5, I placed a Stouffer step wedge in a film holder on top of a sheet of film. I then found a large uniformly lit outside wall, metered the wall, opened up 4 stops, exposed and developed. This one neg helped me home in on my film exposure and development and told me more than any advice I'd read in magazines (what we did before the internet). Eventually I picked up an old densitometer and really calibrated everything. Now I'm coming back after a decade long hiatus and I'm starting all over again with new films, new developers and new papers.
So which step in the Stouffers' wedge did you use that determined your film speed?