Actually, I do not like to go into great detail because it can often do more harm than good when we do not have a professional at our side guiding us through such changes. There is a lot more than I will describe here! These points are my observations of AMATEURS. The discussion for advanced playing is much different! The reality of amateur players is the limited amount of practice time, but the need to "get through" rehearsals and concerts. Good band leaders rehearse more when it gets close to the concert to build chops and consistency of playing, but many will moan about the first rehearsal after Christmas vacation! My observation here apply to these players! 1) more lip in the mouthpiece = greater vibrating area = less critical placement 2) when the chops are tired, more room for swelling = you can play longer 3) better sound when you don't practice as much as you should 4) tonguing is less critical because the large vibrating area is easier to set in motion. The sound "speaks" easier 5) the "bigger" "darker" sound helps a section of amateurs to blend better. Smaller, brighter sounding mouthpieces stick out easier 6) The bigger mouthpiece is a constant reminder to take a big breath and it helps you get rid of that air, preventing it from backing up One possible disadvantage of a big mouthpiece is quoted as less range. I have NEVER had a student that has lost range because of a bigger mouthpiece. Sometimes the switch from a 7C size to a 3C or 1 1/4 took a couple of weeks to get used to. After that - no losses. The advantages of a smaller mouthpiece for a more advanced embouchure are also clear. Here we do not have problems with notes not speaking, size and "color" of the sound, range or flexibility. For an advanced embouchure, a smaller mouthpiece means less work when playing as a SOLOIST. A section has different requirements. That is why the symphonic players generally use bigger mouthpieces - the section sound benefits. If they all would switch to smaller mouthpieces, that would work, but it would probably be harder to transfer what is in their head to the real world. I have had students with more mature embouchures that have switched to smaller mouthpieces to play lead. In the beginning the range was (much)worse, but after several weeks improved dramatically - accompanied with a much brighter sound, less suitable for symphonic playing.