On my G22 1978 I attach some photos to illustrate what I did:
An ordinary rubber P list bought from Denmark with 6 mm tube and 1 mm thick "bottom". Contact glue and glued to the roof itself. Do remember not to include the rear side of the sliding roof. If I recall correct the tube (top of the P-list) should be 4,2 mm.
On the rear side of the sliding roof you have to use a narrower 4,2 mm P list and fasten that the same way as on the roof itself. But: YOU HAVE TO SHORTEN THE BOTTOM OF THE LIST AS THE SLIDING ROOF IS AROUND 1/4 "- 3/8" "THICK. The list in the roof itself teams up with the rear list and seals the sun roof.
Good luck as I presume the sliding roof is the same type as on my car.
Gunnar