Did you say you 'balanced' the Ross Damper? I don't think you should have to - it should be balanced from factory.
Also - if you can feel very noticeable vibration - even free revving, then I wonder if you haven't got something more serious going on.
FWIW, I couldn't 'feel' anything wrong with my engine - it just kept blowing power steering belts off (and now the cambelt)
Sure will be interesting though if a stock balancer fixes it.