I agree with Merlin on the opening of the Selmer C*. As to your question, it depends on what you are trying to do. I spent at least 10 years using a Baritone C* with Vandoren blue box size 5 reeds. I thought the mouthpiece responded well with those reeds in Wind Ensemble settings and Solo setting as well. Recently (The last 2 or 3 years) I have changed the way I play and I don't play anything stiffer than a blue box 3. I ditched the C* and got a Vandoren Optimum that I had Brian Powell open to a .080 and rework into a super dark player. My advice to you? Experiment with reeds before you ditch the mouthpiece!