1979 KZ750B4 dual brake conversion

I'm considering doing a conversion to dual brakes on the front of my old kz when I tear it down this winter (nowhere near enough stopping power for me to feel comfortable). I was wondering if anyone had any experience with this? Since the fork already has an extra set of bungs for the caliper, my primary concern is what size master cylinder to use for the swap, or what parts bike to look for on ebay. Do 1980+ 750 four cylinders have dual brakes, and if so, would that master cylinder swap on easily? I would really appreciate the help...
By the way, I do intend to swap up to a set of stainless lines.

I have done three of them so far

Use the master cylinder on your bike, no need to look for another one. If you look on the underside of the master cylinder, it should say 5/8", and that is the size that Kawasaki uses on the KZ1000's with dual disk brakes. I generally use the calipers off a KZ1000, but the ones of a KZ650 SR should work. If you get a chance, get the rotors off a KZ650 SR, as they are thinner (less weight) and they are drilled. You can use a brake splitter off a 650 or 1000 also.

I also did the swap. I used my 77 650B's master cylinder, the discs are from a 80 750LTD and the calipers are from an 82 550GPZ. I used the single discs splitter, with a longer banjo bolt that holds both lines.

I have a set of dual disc calipers around from a 79 650SR around here if you need them

Thanks for the advice guys. And I might be interested in the dual disc calipers. How much $$$?
Also, you guys seem knowledgeable enough, so here's another one for you...any idea what finish the motor on my bike came with from the factory? There's some cheap black paint on it right now (well, I should say, flaking off) although I suspect it was originally just the metal.
Thanks again.

79 750B motor was painted with an aluminum paint. I have slowly been stripping it off to paint one black.

I used a set of calipers from a 79 1300. They slipped right onto my 79 750B.
KZCSI