Lots of very interesting observations, thanks everyone. I guess for grain I already have the 1600 in the F3. And I do like grain sometimes. I've used HP5 and FP4 in 120 format where the grain in HP5 isn't an issue when enlarged pretty big. I think I need to try FP4 in 35mm and see how I get on with it. I'm usually trying to maximise depth of field, so the slow down in shutter speed may be an issue. I have thought about a move to a different t-grain 400 film but thought I'd mess around with what I know a little about first before a total change, and HP5 in XTOL is what I know best.