You probably got the job done already, but the following may help others who read this thread later.

Below are links to detailed step-by-step instructions for inspection, removal, and re-installation of the cylinders. The instructions rate the degree of difficulty, as well.

There are 12 top hydraulic cylinders in Models 90-96, and 11 in Models 97-02. The models from 97-02 have only one tonneau cover lock, as opposed to two locks in the earlier models.

2 Front lock cylinders - easy to do:
http://tophydraulicsinc.com/R129%20Front%20Locking%20Cylinder%20Removal.pdf

2 Rear lock cylinders - easy to do:
http://tophydraulicsinc.com/R129%20Rear%20Locking%20Cylinder%20Removal.pdf

2 Tonneau cover lift cylinders - easy to do:
http://tophydraulicsinc.com/R129%20Tonneau%20Cover%20Lift%20Cylinders.pdf

1 or 2 Tonneau cover lock cylinders - easy to do:
http://tophydraulicsinc.com/R129%20Tonneau%20Cover%20Lock%20Cylinders.pdf

2 Bow extension cylinders - not hard to do; requires some patience and following the instructions exactly:
http://tophydraulicsinc.com/R129%20Bow%20Extension%20Cylinder%20Removal.pdf

2 Main lift cylinders - medium difficulty; it takes some time to get all the panels out of the way, but that is exactly where you save the big bucks compared to paying a shop for doing it:
http://tophydraulicsinc.com/R129%20Main%20Lift%20Cylinder%20Removal.pdf

Top Hydraulics upgrades and rebuilds all hydraulic cylinders for all Mercedes convertibles, plus BMW and Porsche. Top Hydraulics has developed longer lasting seals with PTFE back-shells. PTFE is the chemical acronym for Polytetrafluoroethylene, which DuPont has trademarked as Teflon.