I have been developing Neopan 400 (rated at 400) in Rodinal Special. I've ran out though and won't have time to buy more before I go to the darkroom tomorrow night to develop film .. where they have a stash of Kodak TMax developer. I'm looking for a suggested development time ... The digitaltruth chart suggests 6 mins at 20C with a 1:4 dilution. I'd prefer to dilute 1:9 (or more?) so I don't use as much and have a longer development time. What would be likely to be good? 10 mins at 1:9?