I just wanted to ask few quick questions:

Are the Light top/Heavy bottom strings sets just for drop tunings? Or you can use with other tunings like Standard or D to achieve more powerful rhythms?

What are hybrid strings? Are they good for metal?

What's the differences between Elixir Nanoweb's and D'Addario's strings?

Elixir's strings is good for metal (I know, my eyes only see metal )?
I use light top heavy bottom for D Standard. Beefs up riffs nicely.
Dunno about the elixirs, no experience..sorry man
No, you can use them in any tuning you want.

Elixir's Nanoweb are coated.

I don't know, I've never used Elixir's for metal. I'm sure if you got a heavier set they'd do just fine.
I use Dunlop's 0.09 in my jackson and they suck...badly. And they rust with ease.