Dee8go,
The 123 service manual CD from MBUSA Classic ($20) has the instructions for removing the sunroof. That's the only way to get to the rear seal. After replacing all the seals on my wagon, I'd say that the sunroof seals were the most difficult to replace. Only because the new seals were really tough to get into the slots for them and I didn't remove the air dam at the front. Once the seals were in, my sunroof didn't close all the way anymore. I had to follow the instructions for adjusting it and it is fine now. Where did you get the felt strips for the sides? Mine were fine but I may want to replace them in the future.
PS: if the plastic trim cup under your sunroof handle is beat, you can get a new one from the dealer for $12.
You could get some sunroof paste and lube the tracks while the roof is out.