Re: Yamaha Tenor Sax Mouthpiece
I've been very happy with the three Vandorens I have (two for tenor, one sop.).
If you really want to stay close to a Yamaha 4C opening size, the closest Vandoren would be a T25 or TL4 ('Optimum') V5.
If you're willing to stretch yourself just a bit you could go for a T45 Java. It's a bigger opening, but not by that much, and it's more stylistically versatile than the V5 (which is designed for classical).