We are seasoned vets of one contest. All the above is great advise and I would only add is to make sure you cut the ribs apart so you have at least 6.
The Brethren are a great bunch of people and all willing to help.It looks like you are set to have a good time, and at the end of the day...
I'd post a pic of our rib box, but we didn't take one.
Grill Dome- Super Dome
"The Twins"- 2 Large Grill Domes
Weber Smokey Mountain