I would make more than 200 to play it safe. With a 1000 people, they will go fast. Unless there are several vendors, then less would be okay.
Maybe you could make some nuetral so that if you end up taking them home, you can still gift or freeze them. You could also do the extras as mini cookies so it doesn't take up too much, but your cookies are still there. I would hate to run out right away and you can alsways freeze any left overs.;o)