I have dark full body paint so the white or translucent tape approach does not appeal to me at this time. Nor does using the same caulk that came on the coach. I called a Winnebago dealer and the current caulk sold by Winnebago for this application is clear NuFlex 640.
http://www.nucoinc.com/pdf/Specialty...ts/640_TDS.pdf This is the caulk Winnebago sends the dealer now under the standard part number. Previously it was another brand. The caulk on my 2008 Destination cracked in the middle of the caulk and did not separate from the adhesion points (rail edge or fiberglass roof ). So I reviewed the specs on the clear nuflex 640 and looked for something with the same great adhesion but more flexibility etc. I fianlly decided to use clear Geocel Proflex
http://www.geocelusa.com/core/prdb/public/php/get_pdf.php?pdf=prdb_product_tech_data_sheet_pdf_2 4.pdf
which I got from Ace hardware. The data tech sheet indicates a much higher elongation/flexibility than the nuflex 640 and does not contain plasticizers like the nuflex may contain. The cure time is longer on the proflex but that might be a good thing.
Greg