I have ZERO experience with the midwest, so can not compare.
I do not know about AR and LA, only FL, GA, and AL.
But,
Down here "sweet" rules except for Beef.
The judges do not seem to like thick sticky sauces, as with LOTS of honey, most of the time.
You might want to stop at one of the main chain BBQ restaurants to see what folks are used to, if you have time.
I know one of the big chains in Southern Al uses tweaked Cattlemen's and that is a good starting point for that area.
A touch of heat seems to work, but needs to be subtle. I have seen several of the lady judges just kill the score if heat or salt is not carefully controlled. They are blessed with more sensitive taste buds than us guys.
We used Blues Hog for awhile. Taste scores were either at the top or bottom of the scale. A totally unpredictable profile for this area, although I love it and use it at home a lot.
Vinegar works sometimes (especially on butts) as long as it is in moderation (like all things).
I have seen sliced pork do "OK" at Douglas for Best of the Best.
But, otherwize it seems to be mostly pulled/shredded/chunked on the pork side.
Baby backs and Spares seem to do equally well--just a matter of what you cook the best.
As Butcher said--I would not change much from what you do are you will be shooting in the dark.
Just tweak it a bit in things that you are comfortable with tweaking.
Probably not a lot of help here--but maybe a thought or two.
When you are in FL--give me a buzz if I can be of help.
TIM