Hemi,
I went with Selleys All Clear Multipurpose which is co-polymer. To be honest I was torn between this and Selleys Clear Storm Sealant. Time will tell if I made the right decision
The finished appearance and feel of the Selleys All Clear Multipurpose is very similar to the Lexel that Leo used when he built this POD before me and he had no issues.
Let me know which way you decide to go.