I wouldn't recommend a Selmer jazz mouthpiece on a Conn New Wonder Series II horn. The Selmer horns are a different breed than the Conns, especially an older Conn such as yours. The older Conns require a mouthpiece with a large, open chamber, and a longer shank. Most of the Selmer mouthpieces that I have seen do not fit this criteria. I would definately try the mouthpiece before buying it. Check the intonation. The Jody Jazz ESP mouthpieces work well on the older horns like yours. I play a Conn 10M tenor and use either the ESP or an Otto Link Super Tone Master. Most Berg metals I have played are fairly bright. What model Berg are you using? I'm assuming that your sax has metal resonator pads, correct?