Hydraulic Clutch increase disengagement?

That looks like the Hebo kit. I fitted one to my CR500. I have normal size hands (sz 11) and found with the lever adjusted as far from the grip as possible and minimum freeplay I can start in gear easily. Clutch modulation and feel are great too.

I think it should do what you want.

Sounds like your clutch basket is dished out. Shouldn't have to pull that far for full disengage. Will it start in gear?

If the inner and outer clutch basket and the actuator shaft are in good shape the KDX will start easily in gear. Pull your clutch apart and look where the plates contact the outer hub and where the metal plates contact the inner hub. The fingers on the outer hub should not have any grooves deeper than a couple thousands. If you have deeper grooves the plates will "cam" under torque when running and put pressure on the plates. If the inner hub has grooves in the spines the metal plates get stuck in those grooves and can't float enough to relieve pressure on the clutch pack. If the end of the actuator rod is wore out it can't do a full release stroke. My guess is based on the age of your bike you have a little of all three. Your first reaction is to file the grooves out of the hub. That fix is like a band-aid with bad glue. The surface of the figures are hard coated and once you go through the hard coat you are into the soft aluminum and if wears fast. The other problem is you never get them perfectly even with the other fingers, then you start breaking clutch plates. If we need a clutch I always replace them with Hinson parts. They wiil be the last clutch baskets you will need for that bike.

Any bike parts guy can get them, they are offered in the Parts Unlimited catalog. I have also bought and sold them on Ebay.
It is not true there is only sand in Florida, we also have mud. We're on the east central Florida coast (Vero Beach) but ride Hare Scrambles and GNCC's from Georgia to South Florida. Center of state has some great old mining areas, so we do see our share of hard pack and rock.