I installed the NGK BPR6ES today. With a little grease on the threads it hand tightened smooth as can be. The OEM Bosch R6 plug was rough to get out with ratchet and plug socket.
The black Bosch tip verifies what the dyno test read regarding the air/fuel mixture. Would a hotter plug be a better thing to have in there?
Some greases tend to cook off at temperatures around 250 degree F while some of the special wheel bearing greases can go up to 380 degrees F.
The spark plug in an air cooled engine gets hotter than 250 degrees.
Without knowing exactly which grease you used you could be fine or the grease might cause a removal problem.
The Anti-Seize stuff is good to higher temperatures and it doesn't cost a lot. Next time you buy a spark plug you might want to get a small tube if it.
A little goes a loooooong way.
When your applying Anti-Sieze apply it to the threads only. You want a bare metal to metal contact between the spark plug, the gasket and the cylinder head.
As for the Dyno test, your engine was running at max power and although I have no idea what the computer mapping on a RE is, max power usually requires rich mixtures so I would guess that is what your bike was getting during the test.
Unless you plan on running your bike at its limits I would hold off on getting a hotter spark plug.
Run the new plug for a while and then check its color. I'm betting it's just about right for daily riding.