The ESP Guitar Company

Hello everyone, I am planning to place a custom order soon and I wanted to ask a few questions to make sure I'll be getting what I wanted. The guitar will be a seven string baritone, mahogany body, maple neck through, ebony fingerboard. I was thinking of putting blackouts in it. Do you think that would sound good? I'm looking for a very heavy, thick chugga chugga sound. I play a lot of metal, not many leads, Low string is tuned to A. I could also do an alder body... I'm not totally sold on a mahogany body. Also, are blackouts the same size as emg pickups? Meaning, if I wanted to change them out at some point to emgs, would I have to make larger holes in the body to accomodate them? Thank you for any help!