The first thing I would say, is what is his diet and exercise regime?? If he is getting too much feed for his amount of exercise per week, he is not able to work off enough energy, and at shows horses tend to be more anxious because of the excitement. A new bit will not be a fix for him, changing his feed and exercise will most likely help if that is the case. Another, if he is having issues staying calm and collected during his classes, why would you stall him inbetween classes?? That does not help reduce his energy level, it makes it worse. You will most likely need to ride him between your classes, to tire him out a little bit or until you can get him to calm down and listen to you rather than being pushy and doing as he pleases just because it’s a show. Also, has he had training to be a show horse or have you just been riding him on a regular basis?? Generally horses that do not have the experience and training in the show ring will get anxious in a crowd of other horses, especially an OTTB; all his previous experiences with other horses was to be faster than them. What I would suggest is a “harder” work schedule for your gelding and at one of the shows, use it as a schooling show. Prepare him as you would for a normal show, get him all cleaned up and you can even wear your show clothes. But before you get into the ring, turn your number upside down. You will not be placed because your there to teach your horse that the show ring is not a race track, that he needs to listen to you, and that its okay to not be the fastest horse out there. You are allowed to use training equipment if you use any during practice (draw reins, training rings, etc.). If you get the chance before the show, you may even be able to ask the judge to still write comments for you just so you can reflect and have some things to work on. Iv’e been showing paint/pinto horses for a few years now and I’ve even had to do this with my horses that have had $20,000+ worth of training. Horses are animals and every now and then they get into a funk and need a refreshers or to be reassured. Also I would suggest maybe even trying a calming supplement (SmartCalm), it worked wonders for my paint mare who would be a nervous wreck at shows, we no longer have to use it because after she realized that shows aren’t a scary place, we had no need for it anymore. It is not druggin gyour horse, it just helps them with the nerves so they can be calm and perform. Good luck!