We use the Mack silicone earplugs also. There are so many in the pack that I took one single one, separated it (ds's little ears were too small for a whole one), and then put them into the holder for a pair of contact lenses (you know the little case that has the screw off top and is about 2-3 inches long). The screw on lid keeps them from drying out and I can drop them in the pouch of the stroller and be sure I don't forget them, since they are always with the stroller when we travel.
Now that ds is getting older (he'll be 5 in a couple of weeks) he seems much better about the noise. But I can tell you, he was terrified the first couple of times. Made us leave the park and only enjoyed the fireworks from the parking lot at MK (where he could see the explosions but barely hear the noise). Now, we can get front and center seating for Illuminations or the MK fireworks as long as I put the plugs in just before.