Just to add to the data already given, the stock solutions keep for a very long time, I've had my current working stock for a little longer than that. You'll see a color change when you mix the stock solutions and the water- that's good PMK.(posted 8890 days ago)Also, this developer is exhasted *fast* when it comes into contact with air. If you fill your tank completely, you'll have a *lot* better results and more consistancy. I use 1L at a time, which is 10ml and 20ml of each stock solution - it lasts a while :)
You'll want an alkalai fixer for the stain, PF's TF4 is great - and it's said that you don't have to do the after bath in the exhausted developer if you use it. I do both TF4 and the after bath most days though.
The 20 min. final rinse enhances the stain, don't skip that step.
Finally, pyro is toxic. Don't get it on your hands if at all possible. I'd recommend wearing latex gloves during development.
It's an awesome developer, and Delta 100 in 120 works well with it for me.
Paul