Selenium does correct a green cast if you're getting one. I've been developing in Agfa Neutol WA, but will start experimenting with Amidol soon. I don't find that Azo has a green cast with Neutol WA, though it does slightly with Dektol.

Be sure to time your toning with Azo in selenium, though, and until you are sure of how it works with your particular combination, make sure you have some spare prints in case you go too far. When you cross the line from max black to purple-brown it's very sudden and irreversible. The purple-brown is actually kind of nice for certain images, and you can vary the extent of it with careful timing.