This page will give you an excellent explanation of how it all works together:
Brake Articleİ by Dean Oshiro
For a MC, I highly recommend something like this:
I use 3/4" for front and rear. The calipers are also Wilwoods - 6 piston fronts and 4 piston rears. I think you get much better performance and balance with a MC like these, because it's much easier to adjust the balance. Most Roadsters need more rear bias than the average car, and so off the shelf single MC's are not really built for that.