Chris, Myself, I would recommend using only stainless steel spokes from Buchanan Spoke & Rim -
http://www.buchananspokes.com/ - Buchanan's have been in business for around 50 years. Top quality, they do wheel set up for many racers at Local & National levels. SS spokes do not tarnish & look every bit as good as new clear zinc plate. You can get the nipples from Buchanan also. I had mine yellow zinc plated. SS spokes does run counter to an 'exact' restoration, but it's my preference. Otherwise, you can have a set of used spokes & nipples new zinc plated for less money than buying front & rear sets cost form Honda. Only problem, if having old nipples replated & your nipples are buggered, then you will need to find replacements. Honda only sells nipples with spokes. They do not sell a nipple or a spoke individually. The round bead rim and the square bead rim use the same spokes. If I recall correctly, the later CB750 rims use a different spoke p.n., than the early CB750 rims. Go to Buchanan's website or call them - they can set you up with the correct p.n. Or, if you want, i can look through my receipts and get the the Buchanan p.n., if you're interested.