Hi,
Whatever you take from Vandoren (V5 or Optimum) will give you a bigger, powerfull, full, with projection, more body............... sound than Selmer. Your Selmer is very closed, it will give you a little, poor and maybe thin sound.
Vandorens are a little more difficult to control than Selmer, the begining could be a bit hard, but you will get very good results.
IMO the Optimum series is a the middle of the road between Selmers and the V5 series. Easy to play, bigger sound than Selmer but smaller and poorer than V5. V5 has a more complex, powerfull, full, bigger .......sound.
For me the best classical sounding mouthpieces are:
-A27: The best, the bigger and fuller tone.
-A28: near but a little bit body.
-A17: a little closed. I am selling one in mint condition.
-Optimum series: easier but litttle sound and power.
You also can have a look to this, this is me in other thread:
"Here in Europe the most used mouthpiece is the Vandoren V5 A27 and then A28.
I find Vandoren are very good ones. The V5 (A27, A28, A17) series are very versatile and polyvalent, they are a little bit more difficult to control than C*, but they are more powerfull with a richer and more complex tone. The new Optimum series is in the middle of V5 and Selmers. Perhaps you could have some "problem" at the first time with the V5 series, but with a little of work you'll find them great pieces.
But certainly, the first matter is what are you looking for in your mpc?
At the beginning I started to play with a C* (it is an standard), then I switched to a Selmer Larry Teal, great tone, more beautiful than the C*. And the final step was the Vandoren V5 A27, great tone, big, full, warm rounded........, slightly more brigth than the selmers, perhaps a little, little, little buzzy but more powerful and with a great projection. The ideal mpc for ochestral and band work. I don't like the Morgan, it is a good mpc, great low, but lacks projection."
Good luck,
Anselmo