Second test with fresh Shanghai GP3 100 film in this size (3.25″x4.25″). Processed in a Jobo expert drum without pre-rinse and water instead of stop bath. Looks like there is still mottling and uneven development. Maybe this film doesn’t like constant agitation? More testing needed. For scanning I made holders from old sheets of 5×4 film. Seems to work well and no more newtons rings.
[Tech info:] Graflex Super D 3×4, 152 mm Kodak Ektar lens, Shanghai GP3 100 @ ISO 100, processed in Rodinal 1+25 for 9 mins.