Got a 99 6R..you are right, the oil should be half way up the sight glass ( make sure you have the bike upright on level ground. To top up theres a plastic plug on the same side you undo and pour in the oil through..you will need a funnel as its a bit tricky to get it in the hole..Im using castrol GPS which is a fully synthetic oil and have got over 30K miles on the clock with no problems..this type of engine is best with synthetic..dont know about insurance, depends alot on what type of risk they think you are ring around and get some quotes or look online
you can also check with geico… they are usually pretty good.
other companies will depend on where you are.