You can't sell it if you don't bring it.
That said, you don't want to cram your booth so full with product, your customers cant actually see anything. You want your display full, but not overwhelming.
Multiples are fine, but put out a variety that showcases your style, and represents various price points (if you have them). If they are looking for something else, let them know you have back stock.
If you will be taking custom orders, be prepared with a form for details, be sure to get payment (at least 50%, if not 100%!) shipping info and their contact info, and be sure to give yours.
Good luck!