Re: custom molded ear plugs at home?
I would be very wary of trying to do your own earmolds. Making earmolds safely is a specialized skill that requires training and practice, plus experience. Trying to make your own earmolds is sort of like trying to cut your own hair or massage your own back, with the one major difference that you can seriously injure yourself doing an earmold incorrectly. It is one thing to cut yourself while shaving, or nick your ear trying to give yourself a haircut, those injuries are generally minor and will heal by themselves. The possibility of perforating an eardrum trying to do your own earmold the first time is real, and that is an injury that is potentially much more serious, especially for someone involved in the music business. The website does caution people about the possible risks, but does not provide adequate instructions in how to avoid those risks. Rather than gamble with your ears, I suggest leaving the making of earmolds to audiologists with appropriate training and experience.
An additional issue the ear bud website does not mention is the problems caused when a sealed earphone is so short that it leaves a large empty space in the auditory canal. When you talk or sing, this empty space generally causes amplification of certain frequencies similar to what you hear when you close off your ear canal with a finger and sing. This is called the occlusion effect and can cause some sounds to be much louder than others. At best it is annoying and distracting, at worst it can cause overexposure to certain frequency sounds that are amplified much louder than others. Avoiding this occlusion effect by proper fitting of the earmold takes much skill on the part of the audiologist making the earmold, and even experienced audiologists sometimes have to re-do earmolds that do not fit quite right.
The solid occlusion earplugs, if they fit well, will attenuate highs much better than lows, and don't work well for musicians or singers trying to play with them in. You definitely don't want to make mixing decisions while wearing full solid occlusion earplugs. Much better are the "flat response" musicians' earplugs designed for a relatively flat attenuation curve, at least up to about 8KHz. Generic ER-20 earplugs are available in several sizes and brands, and provide enough attenuation for most music venues. The time and money you invest in trying out different sizes and shapes of the ER-20 musicians' earplugs is trivial in comparison with the costs of treating an injury that could occur trying to make your own earmolds. The generic earplugs cost about $10-20 and custom molded musicians' earplugs made by a qualified audiologist cost around $250 in NYC, probably less outside the city. The risk of injury may be low, but in my opinion, it is too high to gamble. Similar arguments can be made for custom molded in-ear monitors.