Few questions.

a) the obvious any recommended settings one
b) will a Tubescreamer or similar OD do for my tone what it does for most amps?
c) any pickup recommendations for a mahogany bodied guitar with a rosewood fretboard and maple cap?

Sound wise: Think Iced Earth and Primal Fear for rhythm, Gus G/Michael Amott for leads. Using it with a PRS Allender SE (stock for now) and a Marshall MF400 cabinet (400 watts at 8 ohms).