I recently used Seattle Fabrics 200D TPU coated Oxford https://www.seattlefabrics.com/56-58-200-D-Heat-Sealable-Coated-Oxford-2950-linear-yard_p_44.html for a few accessories since I’m based nearish to Seattle and they sell in small (0.25yd) increments. I found that it is air and watertight, but Matt’s fabrics are still definitely the best in terms of workability and feel, with what seems to be a more substantial TPU film than the Seattle fabric. I also experienced more shrinkage while welding the Seattle Fabrics oxford, even when tacking it in place. Nonetheless, it was perfectly acceptable for small projects, and could be a good option for US-based folks. For bigger projects, definitely go with the DIY Packraft fabrics; they remain the best.