Hey from Memphis glad you enjoyed the bbq. Next time try The BBQ shop on Madison that is true Memphis BBQ. The mac and cheese is not a representation of southern cooking our mac n cheese doesn't look like that. For soul food try Bones and Yams the best soul food in Memphis or 99 cent soulfood express. Bones and Yams food is cooked to order so it's always hot. Best catfish is A and J's the mac and cheese is delicious and the fish is fried to perfection.
Glad you enjoyed it! Personally, I prefer the dry rub, them dip in into the BBQ sauce. Different sauces are unique to different regions of the US. My favorite is a mustard based sauce from St Louis, or a white BBQ sauce from Alabama.
There is no standard. In the big places, you have people from everywhere with differing preferences. Some places will have 5 different sauces on the side for your choices.