Front Disks: 5 x 4.75" or 5 x 5"

[Longstep70]

I noticed the CPP front disk conversion has 5 lug rotors with the car 4.75" bolt circle and the ECE (and others) kits have 5 on 5".
Do the CPP kits have the big 12", 1 1/4" thick rotors? Are they using car rotors or truck pieces? The ECE catalog has a line about truck rotors using larger bearings than car stuff and maybe braking performance not being what it should be if using car components.
I can't decide whether to try for a 5 on 4.75" conversion or the more common 5 on 5. The 4.75" kit would be much easier for me with wheels as I have stuff from my Camaro i could use; plus the choice would be greater.
Maybe someone who has CPP stuff could chip in on the rotor sizes and bolt pattern?

Andy