You could do two things to lower the ride height:

1 - install a thinner rubber shim on top of the spring.

2 - install a shorter spring, maybe cut off a coil or two from the stock spring?

After that then yes, you would need to adjust the control rod for the suspension valve to "reset" for the lower ride height. That will be a matter of trial and error. Adjust it so the arm is in the neutral position when the car has a full tank of fuel and whatever else you consider "ready to drive". Add about 75Kg or so, and that should be enough to activate the valve and raise the height back up close to the "new normal". Adjust control rod as necessary.

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC