This is Locost mentioned before - with R6 shocks
http://www.youtube.com/watch?v=odehGEqqo1k
But - it has different front suspension (shock angle) so... for Haynes Roadster maybe R6 aren't best choice.
I found spring rates for SV650 on other site:
1999 - 2002 SV650 and SV650S have 510 lbs/inch - 9.129 kg/mm shock spring.
2003 - 2008 SV650 and SV650S have 430 lbs/inch - 7.697 kg/mm shock spring.