Re: coolant leaking out
Most coolant expansion tanks don't have overflow lines. This is because the tank is there to catch the overflow from the radiator as it expands. The fluid level in the overflow tank should be at the full when cold line.
The two overflow lines that exit the fairing behind the engine are for the fuel tank.
Coolant shouldn't be coming out of the tank when the bike is leaning in a curve because centripetal force will keep it to the bottom of the tank. I may climb the front or back of the tank during acceleration and braking though.
I would pull some fluid out before you end up high siding from a slick rear tire.