I think I have a better solution, although it may hurt your ears. I have very sensitive hearing, as well, even though I've never been diagnosed with anything. I had struggled for years with fireworks, gun shots, balloon pops, etc. to no success. I had been wearing regular earphones (no noise muffling technology, though; old ones) for years. Then in 2001, I think, I started wearing a set of ear plugs (foam at that time) with the earphones and they worked marvelously; I could stand IllumiNations and Sea World's fireworks without much flinching; I could hear the music but very little of anything else. Then, in 2002, I tried silicone ear plugs (the ones that are connected by a cord) and they worked even better; they blocked out firework noise completely. However, I noticed last month that Wishes seems to be louder than your average fireworks show, and I could hear the loud thuds from the heart and star and face fireworks even with the earplugs and earphones on. So a combination of silicone earplugs and earphones may work for you. You're welcome to try it. Let me know how it works.
Nellas Elensar