If you purchase rotors with the same offset as the stock ones (can't offhand recall what that is), then the 4P calipers + SC OZ Piega wheels all line up without spacers. The stock wire wheel hub is a bit wider than the OZ hub, which lines up with the 2P calipers.
Spiegler made brake lines to my spec. There's a couple of different ways to route brake hoses; the superbikes use a single line with a crossover between calipers. I tried to mimic the stock arrangement. The Spiegler website has a pretty simple ordering process, I think I just used a piece of twine to establish the needed lengths.
Your stock master cylinder will work with the 4P calipers, but be aware that you are changing the Master Cylinder/Caliper hydraulic ratio by adding 4 more pistons. The "feel" will be a bit different as the stock SC Master is smaller that what you'd find on a 999 or 998S. I just changed the master to a 999 unit, so mine is all stock Ducati in setup.
I just bought a pair of used but in great condition 'snowflake' rotors, brand new tires, and installed an rcs19 brake master cylinder. I'm really hoping that the OZ's and the rotors play nice without having to modify anything. The only thing left to get is the 4pad calipers and lines. I'm having a tough time locating decent looking calipers. I may just buy them brand new and that's that.
How much did you have to pay for your Spiegler lines?