A probem I could see with a draw system is how long to you give someone to get back to you and make the purchase? This could drag the whole thing out and if you give a certain amount of time to reply, someone will miss it and then it will be more haters hating.
I wasn't interested in this sale, but I think it was forewarned ane explained well. As others have said, you will always have someone unhappy when there is a limited supply.