sometimes it is very effective ,if the singer is a baritone to have a contrasting sound, rather than more baritone sound.

I'm a tenor; I'd definitely want a bit of low-end oomph from the 'tina. I think what I'm envisaging is a bit different from your style, Dick. I'll have a listen to Steve Turner. (Thanks for posting that version of Streams of Lovely Nancy, by the way - excellent stuff.)