Just a few more kinks...

Finally, after much anticipation, I've got my maxim x up and running!! Huge thanks to all the Vetran members of this site and many others for their advice, tips, and technical know how. 90% of what I know about motorcycles has come from this site. Any newbies reading this should really heed all of their advice, in the order they give it!

So far it's just the basics;
valves
carbs cleaned and wet set
carb synch (which for some reason solved my not shutting off issue???)
gas tank de-rusted
petcock rebuilt
speedo lubed
new agm battery

Still on the list:
Colortune, resynch, and repeat
Brakes front to back
Clutch
Petcock

So just a couple more questions....
I had gas leaking into my oil pretty bad, so bad the engine hydro locked at one point 8O . That was awhile ago. I changed the oil last night and it was about a quart high and I found a decent amount of metal dust on the drain plug magnet. I normally use castrol 4T 10w40. Should I move up to 20w50?

Anybody know why my petcock won't stop leaking? At first it was leaking when left in the on position, now it leaks out of the bottom. I put a new kit in there, and I've pulled it apart and cleaned it three times. There is nothing out of whack with it as far as I can tell.

The next is my air filter, the answer seems pretty obvious but I'll ask anyway. It has a k&n filter, it came with it. While trying to get it to run, I found the bike ran better with the airbox hole covered. Does the k&n really flow that much more air? I eventually got it to run ok with it in, but my idle hangs a bit...