The single disk setup worked fine, I'm pretty sure it was the Brembo 16x18 Master cyl which also made it quite a sharp braking effort, very immediate, but really worked well and saved loads of unsprung weight.
Just have to watch pad wear as it can just easily eat them very quickly. I did get through one set after just one session of a track day!! I think they weren't a decent set of race pads though
I'm sure I used Lucas pads in the end and they had much better life - just keep an eye on them if you're going single disk.
Any pics of the cut down seat you're using?
Tim