Actually Ventile® looks like a recent version of Grenfell Cloth, from Sir Wilfred Thomason Grenfell, a British medical missionary to Newfoundland and Labrador. He said "That you could not keep a statue warm by putting a fur coat on it. - Clothing must be windproof but must breathe."

Here's the story:
http://www.haythornthwaite.com/GrenfellWeaving.htm

It’s also impervious to sparks from a fire, another important benefit for a survivor.

I feel that the ideal would be a Ventile or Grenfell Cloth type of outer layer over a down vest and layered wool commando sweaters for the upper body, and 28oz Codet Woodsman wool pants with suspenders for the lower body.