Hey Bgrundy
I wouldn't expect you to have any clutch plate problems, nor do I think it is necessary to "completely fill" and drain the case. Just get the contaiminated oil out of there and put the correct amount of new stuff in.
The risk comes from running the bike with the low vis mixture in there, which you DON"T want to do. After the oil change, any residue of light ends from the gasoline will be driven off in your first good ride.
Remember to drain/clean the airbox as much as you can (looking at the pictures, it looks like you still have a factory airbox, not pods) as it may have fuel in it as well, and if so, check and change the air filter, since once it gets soaked, its performance in passing air goes way down.
It's not TOO hard to remove the carbs and clean them, but is a PIA if you haven't done it before. You may want to consider an inline fuel filter, if you don't have one, since usually needle valves get stuck with something that came down from the tank.