Why do you want to split the cam chain? I'm not sure of the particular cam chain tensioner you have but I don't think you have to split the chain to put on any of them that I have seen up to now. How old's the engine, ie how long has it been run since it was last apart? I would also check the compression before I changed the rings. If its still good then I wouldn't bother with it. If its not then I would change more than just the rings. It would probably be worth boring to an over size piston also. Just some thoughts.
Mike O
Mike O