Last year I cooked the COTY contest in Austin, and I can tell you that I was welcomed in, and helped along the way by the teams that cook under the LSBS all the time....and given the right opportunity, I will be back cooking a few again.
Are there differences, yessssssssss, but, after processing some of the differences I was able to adjust some things that I do to help my outcome. I encourage you to give it a try, they are a great group of cooks