Kirk Falk

Hello, I have a 2018 Dominator LT 1000 and I am wanting to stiffen up the ride. What is the best way to accomplish this, tighten the recoil spring up or add air to the shock. I can't find any information on the procedure. Also, since im asking questions........my top end rpms doesnt seem to be where it should be. Max RPM is 6100 and usually drops down to 5800 maxed out. Im just wondering if everyone else has the same experience. Thanks, Kirk Falk