Hi, I'm new to the site. I was a serious college trumpet player back in the 80's, but I ended up in a different career and stopped playing some 20 years ago. I have decided that I would like to start playing again and have made time to practice. I fell into bad habits and was playing a shallow mouthpiece, Schilke 13 A4a, and would like to start over this time and develop more of a full concert sound. I have a standard 7c which is fairly comfortable, but I would like to work into a larger cup like a Schilke 15 or something along the lines of a Bach 3c. My question is whether I should work on basic embrouchure first with the 7c or fight the Schilke 15. I can play fairly well on the 7c but the 15 is very limited right now. I am up to about 30 minutes of long tones and basic lip flexibility with some scales and basic melodies. I am focusing on tone and attack right now and basic physical strength. any suggestions would be welcome.