Ok, I finally painted that dreaded ring!!!
I was not looking forward to this part because it was the biggest area for a mistake to happen.
It took a while to tape and I also used liquid tape down in that tiny groove so the blue stayed where I wanted it to stay. I've seen some of the rings painted down in that groove and I didn't like it.
The only thing that might bite me in the butt is:
I was unable to prime the ring before painting. I was worried about paint build up and getting the liquid tape out of the groove. I plan to seal the edges with some clear fingernail polish, That stuff sticks to about anything. Hopefully this part will never get painted again, If it gets banged up then it will be time to dirty up R2 all over and he'll look like he's been in battle.