Morning Bill,
As a long time judge, most would tell you that it doesn't make any difference in your pork selection as long as it is cooked well. In the real world, most are cooking just plain pork butts.
The St. Louis cut spare ribs are the most popular turn in at the present time in the rib category with loin backs the second choice. A judge rarely sees real baby back ribs that weigh 1-3/4 down as all of these go to restaurants. Most loin backs will weigh about 2.25 to 2.50 down to about 3.00 pounds per whole 13 bone slab.
Chicken thighs are winning most contests with legs showing up once in a while. You also see some white meat as well.
Taking the judging class will help you with your contest cooking but probably not like you think. You will learn HOW to judge a contest.....not how to cook for a contest. They will teach you what is legal how to judge each class of meat. As far as the meat presented at the class, it's only as good as the cook selected to cook it for the class. He could be a great cook or maybe a lousy cook.
Now, here is where you WILL learn....as a KCBS judge, you are now allowed to judge contests and you want to do some as soon as possible. You will see what your competition is turning in. How the meat is presented in the box and just what cuts they are using. How spicy or sweet the meat tastes and how tender is it as compared to yours etc. My friend, it's all there in front of you!! I think you will find that a lot of the turn in taste and look about the same as most good cooks are taking classes on competition cooking.
Congrats in walking in three of the meats this year. I can tell you what is winning in brisket at most contests.
Most cooks are cooking full packer cuts and presenting both slices and burnt ends in the box. Remember, you must nail both of these cuts as each judge will judge both cuts if that is what is presented. If you screw up the burnt ends, don't put them in the box. It's twice as tough when you need to get two cuts of meat right!
The winning cooks, (your competition) are probably cooking the Kobe Wagyu briskets. These are expensive at about $10.00-11.00 a pound shipped to your home. I like the larger ones at about 14 pounds and each one costs me about $150.00 from Snake River Farms. I usually cook one of these and one good CAB brisket for each contest.
You mentioned you wanted to learn just what the judges are looking for....so do all of the other competition cooks. When you get it figured out, please write a book or give a class as I have been trying to figure it out for years!
Have fun at the judging class...