I'm actually looking into making the switch to XTOL or the Adox equivalent at the moment (for cost reasons, currently using DDX for a lot of my work and I like it but I think I'd like another developer in my arsenal). Could anyone give me some tips on mixing/storage/usage/care/etc? I've seen some stuff online but sometimes I find the information to be contradictory.
What! Contradictory info online? You must be using a different internet. ;-)
Other than the standard "best practices" advice such as:
carefully follow the mixing instructions,
store in full, tightly sealed glass bottles away from heat and sunlight, etc.
... you might consider two additional precautions for XTOL:
1. test the your XTOL solution before each use by developing a piece of the film leader to be sure it turns black as expected. As discussed in previous posts, XTOL does not turn dark when it expires, so it's hard to know when it has gone bad without actually testing it.
2. mix and dilute using distilled / deionized water. Kodak puts an agent in the formula which sequesters iron which can cause the developer to fail (due to Fenton reaction). I suspect your tap water would have to be unusually high in iron to exceed the capacity of the sequestering agent, so di water is probably unnecessary for most users, but if in doubt...