Usually it is the length of the rod that goes from the sway bar to the control valve, but I'm not familiar with the E500, so check. If you do adjust, to slow, don't just screw it in or out a bunch all at once!
You should be able to get a little more height without too much trouble.
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!