Cheers guys! You have all been very helpful!
I scan all of my film so I guess 1+1 (!) will be best for that as I will have lower contrast than with the more diluted solutions, but will only use half the amount of developer compared to using the stock solution.
I used the stock solution for my first test and got this with TMX:
and this with Fomapan 200 @ 200:
I have experimented with several developers and films, but would like to concentrate on only using a few and learning to use them well. I think XTOL will be one of the few developers I'll keep using. The others I will keep using are HC-110 (for simplicity, and because I have a nearly full bottle) and maybe T-Max, but I'm unsure about the T-Max, as XTOL seems to be as good, but slightly more of a hassle to prepare.
For film I think I'll stick to TMX, Y, Z, Tri-X, Fomapan 100 (cheap!), the odd slow film like Efke KB 25 and some colour neg and slide film when I need colour.
I have got FP4+ in my camera now and a roll of Acros 100 that's waiting to be shot, so if I like them I might add one or both of them to my list. Does my plan sound reasonable?
Regards
Francis