My experience is with a 380SL but I'm sure they are basically the same. I place the jack under the differential to lift the rear and then place the jackstands as far out as I can on the rear "A frames" (for lack of the correct term). It would be necessary for you to take into consideration the design of your particular jackstands. The portion that comes into contact with the car on mine lend themselves to this placement. Check yours and add the weight slowly.
In the front I place the jack under the crossmember and use the same placement for the front jackstands as I did for the rear. Again caution would be the advice I would give on the first time you do this. Before I get under the car I always push on the corners to make sure everything is supported properly. Better to have it fall off of the jackstands without anyone under the car