It's going pretty good so far with the fixing of the rattling speedo.
Took the petc0ck off and easily removed tank. Removed the speedo, cut the tubing and squirted the RTV silicone in there.
Now Oldfeller2 suggested the following:

Take your silicone RTV gasket stuff and pack it into the gap between the steel shaft and the tubing until you totally fill that little shoulder space and mound up a little heap so it will flatten & squish good when you bolt her up.  Leave this sit in open air for at least 2 hours so the silicone will firm up some -- important step to let it firm up some.  

It's been only 30 minutes and the stuff is pretty darn hard already. I didn't think to calculate Hawaiian temp in there.
Is it possible for the stuff to be too hard so it makes reinstalling difficult?
Not sure if I should wait longer or go ahead and start putting the speedo back on.

Thanks oldfeller2.
I have a question regarding the smaller tubing.
You said to run it from the fat tubing to the first thread. Which first thread? The one that starts right after the smooth metal part, or the one at the top?
The reason why I ask is that now I can't use my 8mm socket wrench anymore cause the remainder of the screw is too long. and the speedo hasn't even snugged up to the tank yet.

Aloha Oldfeller, thanks for your great suggestion on fixing the rattle! It really wasn't that hard. I just get majorly apprehensive when trying something new. I just got to take it on the road, little nervous about that one.
I'll let you know how it went.

Be careful out there, the ocean is a force to be reckoned with! I think there are about as many surf accidents as motorbike accidents. Neither one of them very pleasant.