For a delink job and going to different front forks, .. for the rear you do need to change out the master cylinder to a 14mm diameter. Options.. F4i, VTR1000, RC51, CBR600RR. All use the same base castings. - I just bought a '02 RC51 m/c new, I didnt want to have to rebuild. --- The rear caliper pistons need to be working together. I used a bridge line that works fine, and one OEM brake line from the m/c to the caliper, I think I still have pictures in my gallery. - Other guys have just used 2 OEM lines to the caliper and then even others have just drilled out a path in the caliper so just one line is needed, and then one hydraulic port is sealed.
All work fine.
Please dont forget this step, your rear brake will be crap if you dont.
Photos -- I have been running this setup a long time now, and it still works well.
Cheers