I would say not to deposit any sizeable amount until you've verified that you can withdraw. I put some sbd on there to sell back when it first shot up, and when I went to withdrawal, the basic verification wouldn't go through.
So I went with enhanced verification (even though I really didn't want to), and they apparently didn't like my gov issued identification because I still haven't received a reply to my ticket submitted on Nov 24.
tl;dr send a very small amount to bittrex and withdrawal it before using the exchange in any capacity
thanks @r0ndon