In a pinch you can take a grinder to your 5/8 deep socket and shave down the about half the length of the socket to fit in.... it's a tool you will likely use once during the life of the bike.
Strange - I've used mine three times as of yesterday. Of course, I change those plugs once they have at least 30,000 miles and I have the airbox off for any other reason. Current mileage on the Norge is 121,000.
One thing to remember is that since these plugs don't get changed often they can be sticky, both coming out and when putting new ones in. Not only that, but the frame and the angle of insertion complicate the matter. Be very careful not to cross-thread, as you are likely not going to be able to hand-thread them after the first few turns and will have to depend on a gentle wrench.
