I actually just went to look up numbers for this.
Vandoren AL5
.0661
Yanagisawa 5
.068
.067
Yanagisawa 150
.059
Vandoren AL3
.060
Vandoren AL4
.064
Yanagisawa 4
.063
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.