Turtle, I'm Structural Steel Engineer but I have had some exposure to soundproofing. Even though it wasn't my job I did get to watch them soundproof underground (Subway) train stations. It's spooky watching a train pull in quietly. I'm sure you have calculated your actual living space after the insulation is in, but something else. If you have ever practiced in a sound proof practice room it's a little depressing having your sound disappear into the walls. It's great playing in a hard room that you can make ring. The ultimate is playing up in the mountains. Some paneling can brighten up the sound. Different paints can brighten up the sound also. This is a whole course of study and barrels of money can be spent on it. You're a trumpet player so you have a good head. A little experimenting and I'm sure you will fine the proper balance.