You are wrong. Outdoor Wilderness Fabrics does not carry any of the new 15D Impetus fabrics. You can only get Impetus 15D fabrics from DIY gear supply http://www.backwoodsdaydreamer.com/
Impetus 1.2 is Sil coated on one side, and PU coated on the other side. You can tape/glue the PU side. It has a HH measure of around 1200mm.
Scott is being very honest with the weights of the fabric also. He is calling Impetus 1.2, 1.2oz a square yard, where in reality it is more like 1.05. Same with the other versions. Only makes a difference on large projects :-)
Info on Impetus 1.0 and 1.1, from DIY gear supply:
"Ultralight 15D Micro-Ripstop Nylon. 1.0oz/yd² after coating. 55″ usable width. Heavy Cire coating for excellent DWR and good breathability. Downproof (800fp +).
This ultralight fabric is ideal for quilts, sleeping bags, down gear, hammock overcovers, windshirt, etc. Incredibly soft hand and feel. Impetus has been tested only with 800fp+ down.
"Ultralight 15Dx15D Micro-Ripstop Nylon. 1.1oz/yd² after coating. 59″ usable width. Light Silicone coating for amazing water repellency while still maintaining breathability. Downproof (800fp +)."
This ultralight fabric is ideal for bivy tops, quilts, sleeping bags, down gear, hammock overcovers/undercovers, windshirts, etc. Impetus has been tested only with 800fp+ down."