i'm at 3/4 of the way stiff. you should have 720 degrees of adjustment. this is only rebound adjustment. settings will depend entirely on your setup. koni has a autox setup guide.
http://www.koniracing.com/autocrosstune.cfm
i need to jackup the rear to adjust the rear shocks. don't have to remove the shock. it's a pain though.
it's about as easy as doing springs. you'll need to salvage the front and rear top hats. also make sure the front spring cup is oriented the right way, downward.
also some info from when i was emailing koni:
" The external adjustable shocks come with a plastic knob which indicates the direction for adjustment. Counter clockwise rotations of the adjuster increase the forces maximizing the rebound (make it firmer), thus extending slower, harder. With the shocks set to full soft (clockwise rotation) the shock will be softer, and extend faster with less pressure. There is no double adjustable available off the shelf for the 370Z."