Brake caliper & rotor

All, Rather than "jack" The Hybrid thread, & not seeing what I need in "classified's", I'm fiddling w/a '81 KZ550A1. which now has a KZ650 B1 front end, & am looking to fit a 2nd rotor & caliper to. The parts are all out there on Ebay, But calipers travel in pairs, & rotors seperate. I'm looking for 1, 4 bolt rotor, & 1 r/h trailing caliper. I think '77 thru "79 650 or 1000's will fit the bill. am open to thoughts.. G

If I recall correctly, the 1000 rotors are larger in diameter than the 650 rotors.

I think I have the calipers and rotors off a 79 KZ650SR, I'll try and get out to the shed tomorrow and find them.