I actually just went to look up numbers for this.
So I would personally suggest a Vandoren AL3 or Yanagisawa 150 for a classical mouthpiece. I use the Yany 150 and a Selmer Scroll Shank for classical alto. I think the Yanagisawa 5 you have is more for style flexibility. I have experience with the AL3, AL4, and Yany 140, and Yany 150 but not the AL5.