mad vapes has a tiny little fuse they sell that you can insert in the mod to raise the pin a hair. At 89 cents each, it could be worthwhile. One of my ProV's pin is set a hair lower and I've enjoyed this little fix.
Don't know what to tell you about the ring, though. I'm generally happiest with Sotang, Original kayfun and Unknown manufacturer. I don't think any of those come in black.
Those little circuit board scraps? I've seen them, but never used them. If they're thin enough, that would definitely work, but if it's a problem with that one KFL on all devices, I would think it's easier just to lengthen the pin & be done with it.