I'm only using the cheapest option, Aristo 4 pot with Project Mu 500deg B Spec pads on 315mm discs (std discs are 296mm).By the way, what brakes are you using on Mark X. I saw a few Mark X running around with TOM's brake.
That TOM's brake are mostly just sticker on Advics 4 pot, can put any stickers. On my Aristo I put "Mark X" stickers.