Suspension 03 Prairie 650

Hello All! Looking for some guidance on adjusting the suspension on my 2003 Kawasaki Prairie 650. I bought it a year ago used. I am a big gentleman (300+lbs) and believe the rear suspension needs to be stiffened up. I am aware of what it mechanically takes to accomplish this but was looking for some guidance in how much of an adjustment I would need. Is this just a trial and error procedure or is there a rule of thumb on this many number of turns yeilds this much adjustment? Any help or insight is greatly appreciated! Thank you!

I set mine up, when I had one. 1-2 clicks at a time till I was comfortable with the travel in the suspension. ( I was doubling my wife that season) combined weight
350 lbs. No problems at all. No problems except swing arm bearings, If you hear
any snapping or grinding finish up the weakend ride then get them changed.
Cheap if you do it right away expensive if you let it egg out the housing.

You can get some stiffer springs for the shocks if adjusting the preload doesnt work how you like it,but turning the shocks up should do it for ya