I have no experience with XTOL although I don't think I have ever read anything negative about it, so it is most likely a good product and easy to use. I haven't used the BW-2 either but as for the DI-13, I can not reccomend this developer. I have had serious problems with uneven development when using DI-13. If you want a low contrast developer I would try a pyro developer over the DI-13. As for Rodinal 1:25 and 1:50 are standard mixes.(posted 9587 days ago)