I've been playing again for about a month after a 15 year break, but have a bunch of questions. I apologize for what's likely a long-winded post.
I've built a bit of an exercise based on what I've found online, which consists of doing the following:
1. Starting with low C, playing each half-step for 8 beats at about 40bpm, then repeating starting with G then 3rd-space C.
2. Lip slurs with approximately the same pattern starting with G/C/G, G/C/E/C/G, G/C/E/G/E/C/G, etc.
3. Playing sheet music from a variety of locations until I tire out.
I've been looking at replacing step 1 with the 19/30s method I've read about, but I want to make sure I understand it properly. I start with 3rd space C, play a solid note for 30 seconds, rest for 30 seconds, and repeat with B, then Bb, etc. My goal being to play a solid in-tune note naturally without forcing it out, until I run out of breath. Is this correct, and what everybody is referring to as "long tones"? My biggest fear is that I'm going to do something the wrong way and end up hitting a wall sooner or later.
Are there any other must-do exercises I should be doing in addition to what I've listed above?
When I was in high school, I always believed that with Bach mouthpieces, the higher the number, the "thinner" the sound, but the "easier" and "less tiring" to play. Lower numbers like the 3C and 1½C would sound "fuller" at the expense of being more tiring to a newer player. Could somebody please tell me if there's any truth to this, or if it's just naive teenager rubbish? I have a gold-plated Bach 3C "mega tone" mpc, and a regular Bach 7C that I honestly can't decide between. Everything I've read about mouthpieces says asking 7 people will get me 9 different answers, and to go with what feels best to me. What I don't understand, is what "feels best". I'd RATHER play with the 3C, but it's mostly for aesthetics. I seem to tire more quickly while using it, but I honestly don't know if that's just in my head. Both mouthpieces "feel" the same to me when I press them to my lips, so I don't understand where the comfort thing comes in.
Right now aside from being horridly rusty at sight-reading, my biggest problem is a lack of stamina. After I warm up and play for what feels like 15-20 minutes, I have trouble hitting even the middle-staff notes, and when I do hit them they sound very "airy". Only being able to play through 2-3 songs back to back is unacceptable, but I'm at a loss as to how to remedy it. Will it self-correct over time? IS it a mouthpiece thing?
Any clarifications, tips, critiques, resources, etc. would be greatly welcomed.