Sorry, I do not have any 600RS clutching at all.
I dont carry any clutch parts, no gearing....nothing, sorry!
I dont tune 600RS, does not matter what year. 
If you want to know what to do to lower engagement speed, then Goodwinperformance or Laflamme racing.
If you need weight for your pdrive clutch, then then Goodwinperformance or Laflamme racing.
IF you have a 600race sled and want anything to do to tame it down, sorry, I have no advice, THEN then Goodwinperformance or Laflamme racing.
IF you want lower engagement speed, see Sylvain Laflamme or Goodwinperformance
im not being rude, its not my market and im buried with correspondence, phone/emails etc with what i market - too many emails - i cant please everyone.  Havent got the time to field your 600RS quesitons, please try Sylvain Laflamme or Goodwinperformance
I stay away from race sleds like they're the plague.  
If you want clutching advice, see Sylvain Laflamme or Goodwinperformance.
https://laflammeracing.com/en/products
or Greg Goodwin
www.goodwinperformance.com
Thanks and Good Day.