RE: Update:How long does he need to lay?
That sounds like a good plan. If you did hit guts, you may not find much if any blood. They tend to plug up any entrance and exit holes. You may have to go by tracks or just grid search the whole area. If you got liver he is dead. Even if you only got guts, he will die, more than likely.
Let us know how it goes in the morning, and best of luck on recovering your deer.