This sounds a lot like what I have taught. "Tone" is a perception which comes from the entire set of elements in your sound. It even includes stuff like the attack and release, any hint of vibrato, the steadiness, or even the slightest crescendo and diminuendo. There is a basic level at which the sound production has to have quality, but after that, much of what the listener hears are the fine nuances like attack. You can get even a small bore horn to sound "big". Studio trombone players have used King 2B horns for many decades and they sound huge. Having similar sizes seemingly can sometimes help blend, but most of it are the details of sound production.
Aside from bore size (highlighted in this video), what factors should one consider when buying a trumpet mouthpiece? Thank you in advance for your opinions!
I would advise starting with the rim. Find something you find comfortable that works for you and that you have good endurance and articulation with. Then the cup for the depth and tone you're after. The backbore can be used to balance out the resistance/feedback you like. Hence, a lot of players end up using screw rim mouthpieces... but you may very well find something you like in a one-piece.
