I'm about your weight. Turning clickers is not gonna do it for you if you have the stock springs. Go one way and the bike will be soft and wallowy. Go the other way and you'll discover the meaning of the word "harsh" as you deflect all over the trail. You either have to replace the springs or accept all the ills that go with riding a bike that comes from the factory set up for a 135 lb rider. Correct springs for your weight will then allow you to play with the damping and actually have it do some good. Here's what I'm running:
Front: 0.44 kg/mm (stock is 35 kg/mm)
Rear: 5.2 kg/mm (stock is 5.0 kg/mm)
Rear sag: 100mm
If you can only afford to respring one end, then the most improvement will come from replacing the front springs.
To summarize, the spectrum of KDX suspension solutions for those in our weight class are:
Best (and of course, most expensive!): New front & rear springs and a professionally done revalve
Better: New front & rear springs. No revalve.
Budget: New front springs only.