Dang man, that's fo' questions in one post.
Get you an oily shop rag and hang it in yo' back pocket, not only will you look real cool, you can wipe the oozie with it.
You can run all season with that leak, long as it durn't lose the oil real fast like.
Probly not a symptom of overfilling, you got a crankcase vent, you only three or four ounces over the line. The level should split the window with the bike upright.
If you is one wit yo' Zen bike thing, you should be leaking too.
