Im not sure if this sheds any light, but when I converted from the air shock to my Yacugar - I changed the "ride height" by first being sure that I had the correct rider SAG setting on the air shock (adjusted via pressure). This should be somewhere near 30% of overall travel. Once that was known - I made a judgement as to where I wanted my new shock to sit (height wise). In my case (I'm shorter too

) I wanted the Yacugar to be about 1/2-3/4" lower (again, with correct rider SAG) to help me touch the ground a bit more. So to do this, the shock is built shorter with correct spring/preload (based on my weight and weight of gear I'd mostly be riding with). I lost a bit of overall travel, but now, again, with the correct rider SAG now set, I am that 1/2-3/4" shorter in terms of seat height. A compromise.
The real bonus going to the new shock (over air) is that I don't feel like I'm going to bucked off every time I stop and the rear is unloaded. Another bonus for us shorter folks is that the actual free height (with no load) is not as tall, so its easier to kick a leg over - for mounting and dis-mounting. I can't recall the exact amount of difference there is in seat height between the two, unladen, but its much nicer now.
Hope that helps...
Mike