Arts Supplement?

<p>Hi does anyone know if I should or shouldn't add an arts suppliment to my early application?
I play a unique instrument and I've performed with a decent orchestra, but it means that I have to submit in the application a whole half month in advance (October 15!).
Also, I'm not like, a genius at it or anything, and I only played with the orchestra for three years and went back to practicing on my own. If I list that in extracurriculars, should I just list the instrument, check all 4 years, then list the orchestra name in the description area, or list the orchestra in the activity names section?
Thanks a bunch! :)</p>