Some general thoughts. Start with desired pedal pressure. You will want to keep it under 75 pounds or so otherwise it just can be to much work! Pick your pieces so that are balanced for maximum deceleration by design. That is the balance bar will be centered and the master cylinders are within a size or two from each other. Having the master cylinder close in size will mean that you will have close amounts of travel and less risk of the balance bar binding. Of course you have to balance the components at the wheel to accomidate this. Keep line pressures under the manufacturers recommendations or 1000psi which ever is less.
Rotor size. You can easily calculate the heat generated by stop. Pick a good average speed stop, say 120-50 or something like that, and multiply that temperature rise by 10 and buy rotors with enough mass to accomidate that temperature rise. Pick your pads by this temp as well. A typical weight Cobra a 12.19" iron front rotor is usually sufficient for all but endurance racing. Use a cast iron ventilated rotor, slotted NOT cross drilled. There have been some really good improvement in the vane design over the old straight vanes that do have numerious advantages.
Now that you have picked you pedals (pretty much dictated by packaging and personal preference, I prefer them to pivot from the floor......... you will to!), rotors, pad compound and you know the maximum brake torque required (from the spreadsheet), balance your hydraulic components. Play with the different caliper and master cylinder sizes available to get the proper balance. Be careful not to get to small of a master cylinder compared to the caliper size.
Order your stuff, carefully install and test. If you have a G meter that can be handy or you can use toppling blocks. Get the balance right and use temp paint to verify the system operating temperatures. Use pad compound, bias and ducting as tuning tools. Change your fluid before every event. There should be no need for exotic fluids in this application. Good fluid like some of the OEM stuff designed for high temp or something like Wilwood 570 or valvoline
synthetic should suffice.
HERE IS ONE TRUTH IN BRAKES: There are NO miracle brakes when it comes to stopping distance. If a car can lock all four wheels, then there is sufficient brake torque available to stop the car at maxiumum deceleration. Tuning bias may help a bit (particuarlly OEM systems). Adding bigger brakes and changing nothing else WILL NOT SHORTEN THE STOPPING DISTANCE by any significant amount. There could be slight gains through pad compound (better initial bite), and tolerence/quality (less run out, better seal design etc) but that is it. In fact, you could end with a car that does not brake as well as the OEM system. If properly engineered, what you will end up with is a braking system that at the very least will give small reductions in stopping distance and will vastly improve fade resistance. YOU CAN NOT TAKE A CAR THAT CAN LOCK ALL FOUR AND CUT STOPPING DISTANCE BY 60% SIMPLY BY CHANGING BRAKE COMPONENTS.
By the way, I checked out the spread sheet in the dsr racer link. It leaves out or assumes a great number variables (it states so at the top). VERY IMPORTANT variables. I would not recommend using it to design a system from scratch. Even my spread sheet needs a little thought, common sense and some other factors considered and it includes all the factors that the dsr one does not.
Happy braking!
Rick