Welcome to the new and improved Proflex / K2 Tech Forum!
If you want a firmer rider to work I'd crank up the compression dampening. Don't put it all the way but may be 1 or 2 "clicks" from full compression. And keep the preload where it needs to be. And remember, the more compression you run, generally the less rebound you'll need. So you may want to back the rebound off a little. Just a suggestion. Of course you'll want to back the compression back to normal settings for offroad riding. My Fox Foats have lock out, so I get to cheat. I hope this might help.
Oh and SRP Ti bolts on the shock pivots work fine.