Lovely bike and I'm unashamed to say that I'll be pinching a few ideas from you on my BMW build.
Namely the tank stripe, that's the best example I've seen on that style tank (and trust me, I've looked and looked)
Also, the silencers look great, I'm guessing they're Dunstall style silencers.
I had a suggestion about a top yoke, but then spotted you got yourself a San Jose BMW top clamp - nice find!
I've used a spare bottom yoke with the pin pressed out and flipped over, I machined a recess for the stem nut so it sits flush with the at the edges, with the hex & dome of the nut proud of the top. I removed all the raised castings with a DA sander and various grades of disks, finishing with a bright, clean surface, but not polished - don't want to be dazzled by reflected sunlight when my chin is on the tank
Regarding the wheel colour, this is only my take on it and I'm not having a dig, but the current wheel colour seems to flow well through the bike as it matches the engine and trans, the black might be too much and break up that flow.