Just a quick though regarding SpinnUL. Has anyone tried DIY silicone treatment of any of the various 0.5oz polyester ripstops that are available from kite/sail making sites? Granted the convention seems that "0.5oz" in regards to these fabrics seems to be much more of an estimate than true measurement, and that they use sailmaker yards rather than square yards for their measurements. But if one found a suitable fabric at "0.5oz", ie ~0.62oz/sq yd, and then did a DIY coating, could you approximate SpinnUL?
I'm not actually looking to do this. Just an idle thought. Some of these kite fabrics are pretty inexpensive.