Just done a bit of research on spring rates for R6 shock... they seem like over kill for Haynes:
03/04 R6 shock is 9.85 kg/mm which converts to ~551lbs
05 R6 shock is 10.98 kg/mm which converts to ~614lbs
But you guys say there are people out there with this set up? What's the ride like? .... don't say 'stiff'
Rapid