3M makes a special trim/weatherstrip adhesive that works great; it comes in a small tube and is available at most auto parts stores. FYI, in my experience the seam is located right in the middle rear/near the trunk lock. My only advice is the age old "measure twice, cut once".
I use 3M Fastbond 10 contact cement which is likely the exact thing that was used at the factory. The 3M weatherstrip adhesive will get the job done but it is not made to brush on which is what you need to get even coverage.
i took the deck lid off and turned it upside down on a blanket--i then put 3/4 masking tape where the rubber goes , followed by another lap of tape on the outside of the first lap---then remove the first lap and thats where the 3m stuff goes---i put it on and brushed it out with an acid brush---i worked wit about 2 feet of the rubber at a time until reaching the center under the window---trim to lenght and bond ends together with 304 loctite glue