the mecedes spring pads typically come in 4 thicknesses from 8mm to 23mm at 5mm intervals. Assuming you have the thinnest pads to begin with (unlikely) you'd gain only 15mm in height. Now, my experience to date has been with the W201 suspension, however I suspect that the sizing is roughly the same for all models.
the issue is not in the spring pads, but in the sproings themselves: SLS rear springs are considerably softer than non-SLS rear springs. Most of the weight is borne by the SLS struts. Since you've deleted the SLS, the springs now bear the full weight of the car and the rear, naturally, sits considerably lower.
to resolve the issue you will need to re & re your existing rear springs with those from a non-SLS equipped W126.
'94 W124.036 249/040 leder; 8.25x17 EvoIIs
'93 W124.036 199/040 leder; 8.25x17 EvoIIs, up in flames...LITERALLY!
'93 W124.036 481/040 leder; euro delivery; 8.25x17 EvoIIs
'88 R107.048 441/409 leder; Euro lights
'87 W201.034 199/040 leder; Euro lights; EvoII brakes; 8x16 EvoIs - soon: 500E rear brakes
'70 R113.044 050/526; factory alloys; Euro lights