Well are you going to Superlap to win a specific class? Or at least compete in one? That would be a good of a starting point as any.
Also realistically 500rwkw, stock Brembo items with rotors isn't going to be pulling that up at all well.
More clamping force, more pad area, heat dispersal etc is what you really want.
Look at the normal circuit racers going 10/10s with 350-400rwkw generally get 2-4 laps out of sizeable brakes (356mm minimum). You want more power, yes for only for one lap, however absolute lap time is going to require the most you can get. Most being as per above force/area/heat etc.