While I still think the MMC1 is truly a very specialized mouthpiece for an advanced symphonic player, without seeing you in person, I cannot and will not tell you don't use it. If you were my private pupil, it would take me 5 minutes to see if it really is right for you. I am curious as to what you are looking at in solos. Virtually any really advanced solo requires some manner of multiple tonguing and many "easy" solos do as well but to a lesser extent. Every solo in the back of the Arban's requires considerable multiple tonguing skill. For a true great's take on mouthpiece sizes, check out Jens Lindemann's post here. There is considerable wisdom in his writings. There is some good advice is some of the posts. Follow it. As Mendez said, if you want to learn to play fast, learn to play slow first. Rich T.