I prefer general rules of thumb for tuning suspensions so that I know my suspension is right for me, for my machine, for the way I drive, and for the terrain I drive in.
Rules of thumb:
1) the faster you drive the more compression (clicks to the right) you want, the slower the driving the less compression (clicks to the left) you want
2) the more weight you carry the more compression you want
3) start from full soft and go up by 2 or 3 clicks each time
4) adjust by 2 or 3 clicks when you make adjustments up or down
5) fronts tend to want 2-3 clicks more compression than the rears
6) if the car bottoms out, add more compression
7) take notes every time you adjust tires or suspension and keep a log with what setting you adjusted, what you adjusted it to, and what your thoughts are on ride quality.
As others have noted, tire pressure is a big deal. I tend to run in the 12-18psi range and have a preference for "square" or running the same tire pressure all the way around. Would suggest starting with tire pressure at 18 psi all around, suspension at full soft. If it feels like there's too much chatter (tiny bumpy stuff like washboard) , decrease tire pressure by 2 psi each ride. If you bottom out, add 4 clicks front and 2 clicks rear initially, then go up by 2 clicks each time. As others have said, find a loop that you can run and make that your suspension testing ground.
Also, some people's "slow crawling" is different than others. Terrain and background come into play here. A leisurely trail ride for me is around 30-ish mph, a spirited one can get up towards 50-60mph. We have some pretty good potholes up here but no moab-style rock crawling, so I tend to favor more compression, medium-stiff tires, and less preload. If I was rock crawling, I'd want near full soft and a ton of preload. If I was in the desert, I'd probably want even more compression (to a point), firmer tires, and to drive it like a bat outta hell.
Almost lastly, rider preference comes into play. When I ride by myself or at good clip to full speed, the compression's cranked. When my wife is with me, the compression and tire pressures backed off a bit, but still firm. When the in-laws were in town a few weeks ago, I was at full soft and waaaay slow speed for the ride-along because they're a bunch of delicate flowers that will wilt if they sense a bump (or the outdoors for that matter).
For instant gratification, the setting I ride at most often (with wife) is 18psi square tire pressure, 10-12 clicks up from full soft on front, and 8-9 clicks up in rear. Have 700 lbs of passenger weight, cooler and tools in back, glass windshield, plastic roof, and full soft cab for reference.
Happy trails!
