Hey Ken, I’m looking to start signing metal vocals. I was wondering if your method would help me sing things like Ozzy Osbourne, Joey Belladona (Anthrax), and even some more odd voices like the angry almost non-signing voices of Dave Mustaine (Megadeth) and Tom Araya (Slayer). examples for the last 2 would be songs like Trust by Megadeth or Americon by Slayer. Caught in a Mosh by Anthrax, Crazy Train by Ozzy, etc.
What I teach would definitely help you with the Ozzy stuff. As far as the Anthrax Megadeth stuff, within what I teach (meaning keeping your voice when singing heavy like this) there are components that will help you, such as killer support, open throat and compression techniques. Though my advanced scales focus on vocal range, you can use them (not go as high but develop strength with the support techniques that will help you with this)