you might want to check with Theo Wanne @ moutpieceheaven.com. He does some really nice things with hard rubber pieces

The knights templar find it interesting that you talk of how it feels in your mouth.Yes it is good to get things feeling as best you can but for us sound is paramount.The secret is to know how much lift you require ,depth you want, the all important width if your a hard bop , post bop, or blues person, etc player.If your a link person, hard rubber against metal have similar and different qualities which sends the link people on an endless jeourney.If you require maximum width for example with masive power then that dosent lie in metal as a lot of people think.Also tuning and lay are different with links,metal to hard rubber.Links for us are the greatest ever, may be on a par with Freddie Gregory . But the links are a battle a life long battle it never stops refinement and change.The knights Templar are making reference to mouthpieces here for tenor sax.( Bird lives)

Hi, I play RPCs (Ron Coelho only produces hardrubber mpcs). They sound great! And I play a Lebayle Jazz Chamber 8 Wood(!)-Mouthpiece. Great Subtone!