I gotta tell ya that you don't need anymore brake than this unless you intend to run enough laps in a row to heat them beyond what they can handle. Mine went 125 miles in one day on track and were perfect all day long. This setup is the same as used on short track stock cars, +3000 pounds, and they run on 5/8 mile ovals for 50 laps. Sometimes 100 laps. Thats 100s of brake applications in a row from about 130-140 down to 70-80 or so. One right after another with just a very short straight between them to cool the brakes.
The upgrade is the HD 45 vane rotor over the light weight 30 vane. The, HD's, are what I have.
F1 cars have tremendous downforce and run 2 hour races on tires that are so sticky they last about 30-40 Min's! The speeds are way beyond what most of us will ever see during track days at our local track. Do what you want, I'm just trying to save you some money.
Oh I have 17 inch wheels and 1 inch + clearance all the way around. 13 inch rotors would fit easy with room to spare. The hats are the undrilled 1.41 offset universals. They have a 3/8" thick face and can be turned down for final alignment of the rotor to the caliper center-line if necessary. Run the 1 3/4" diameter pistons up front and the 1 3/8"s in the rear. Put a proportioning valve in the rears and you will be very close on balance. I still have the original GTD master.
last pic of caliper mount