Alright, so I was wanting to learn to scream, and back in june I thought "What the hell, I'll try it."

Well I've been practicing screaming for a while, but I don't know if I'm doing it right.

How can you tell if you are screaming correctly?

And also, I can do a scream like Spencer Chamberlain's low scream, but I want to sream higher for post-hardcore/screamo.

How do I do that?

And one last thing, is Melissa Cross's The Zen of Screaming really that good? Like, will it just show you how to scream like a low, hardcore kind of scream, or could you take the stuff from it and be able to scream like Underoath's They're Only Chasing Safety?

I would really appreciate help, even though this isn't the best place to ask...