[skidlids]

As Phil say its a matter of fine tuning it
I have quite a small Air Gap and have about 30mm unused of my fork travel, but then I like to run soft springs and soft damping settings to suit.

I can get away with this as there aren't many big bumps on most of the tracks, so most of the fork travel is used up under braking and I prefer my bike to hold itself up on the brakes rather than dive to the bottom of the forks, hence the smaller air gap and resulting in a stiffer air spring
So it really is down to individual prefrence