Each time I have declared my overage on liquor, cigarettes, jewelry or watches I have been just waived through and have never paid duty.
Granted the last time I lugged home booze, jewelry or a watch was around five years ago. However, I have went over on the evil cigarettes as late as January and was just waived through.
This is a good thread for first time cruisers. If you have to pay the duty you won't go broke. Remember, you only pay the "Federal" tax on the product and not the state tax.
If you're lucky you will be waived through. If you have to pay, you won't go broke unless you have cases of liquor or tobacco. You are always better off being honest than having the overage discovered and having to go through the hassle and payments associated with not telling them.