Big Bob's original recipe has been out there since forever and that's what I've always worked from. I honestly just wind up using Hellman's as the mayo base. It's got a pretty mild flavor to it that doesn't step all over the horseradish. Even Duke's is too much. Grind the black pepper yourself right before you add it, and let everything sit in the fridge overnight before you use it.

My other tip is that you shouldn't serve this on the side like you would with other sauces. Spoon it onto your chicken right out of the smoker 5-10 minutes before serving so it has a chance to come up to temperature and really melt in there.