To the Light, large format film photography

I could barely see anything in this room when I first entered. My eyes slowly adjusted as I unpacked my meter, loupe and other gear only to discover that my meter would really only return values close to where the light was entered the room from outside. I dicovered that about 6-7 steps from the top was metering at about 2 minutes or so, as was the rim lighting on the doorway under the stairs. I guessed at 6 minutes, started the exposure and stood in the just-below-freezing cold, waiting.

Camera: Wista 45DX
Lens: Nikon Nikkor SW 90mm F/4.5
Film: Ilford FP4+
Exposure: ISO 125, f20, 6 minutes
Movements: 1/2 front rise
Developer: Blazinal agitated first minute and stand developed for 49 more at 22 degrees