I'll give them a look! I measured my calipers and my fronts are 3" pistons and my rears are 2.25". (It appeared anyway, quick measurements with a tape measure)
I bought a brake book which goes into what it takes to figure out proper MC size. It's
High-Performance Brake Systems if your wondering. I'm only about 1/3rd of the way through it but so far its a great book.