Don't eat too many Brussel Sprouts before the exam! I once did before playing the Busser at a competition. The result was catastrophic! I cracked a ripper of a fart just before hitting that top C in the low A(or G can't remember sorry) remember to high C phrase. I had complete diaphragm failure and that cracked C is still echoing around the echelons of that concert hall. The biggest challenge in that performance was to carry on without laughing. As my dear old granny once said "No matter where ye be, let your wind go free. That's what killed our Annie." True to her words i did, and am still here to tell the tale.
Sadly, i don't have any recordings, and i have never come across any. Good luck in your exam. If you are playing in a pokey exam room, don't point the bell at the examiner! Find a position which is both comfortable for you and flattering for your sound.