Hi there.
Believe it or not, my dealer's garage overfilled my st1300's oil tank (you can't see through the viewer, oil fills it all).
Would anyone suggest any draining procedures to get rid of the extra oil?
My dealer did the same thing on me. Since then I have changed the oil myself. If the oil level is high, you can loosen the drain bolt and allow some oil to leak out. Keep an upward pressure on the drain bolt as you are loosening it. This will require 100% focus on your part. Do not move the drain bolt away from the crankcase, keep it touching the hole so that you can screw it back in quickly, instead of trying to look for the hole. It wont take much to bring it back to the right level. you will only have to release 25-50cc of oil for it to come back in range. I cant imagine that the dealer would overfill by more than that. Make sure there is an empty pan under it so that if there is a mishap, you wont have oil all over the floor.
But the best thing is to take it back to the dealer and make them aware of their sloppy work.