If you want darker, you dont want a Yani mouthpiece. Maybe a Berg in a smaller tip opening. The metal ones are good, if you can find a pre-1985 one (which isn't that hard to find). You probably need a more free blowing set up because you're playing somewhat hard reeds on an open mouthpiece. If you're gonna stay with an open mouthpiece, soften up with your reeds, or get a more closed mouthpiece. Meyer and Otto Link still produce some good stuff, but vintage ones can be really great.