Which Seam Sealer should I use?

For silicone coated materials, you want to use Sil Net for seam sealing.  For PU coated materials, Seam Grip should be used.  

For materials will dual coatings (Like our 1.1 Silpoly PU4000)  You want to use Silnet on the silicone coated side, and Seam Grip on the PU coated side.