Brett,
Down jackets
The ones I was talking about are the like of the Western Mountaineering Hooded Flash Jacket , about 260g in M, the Patagonia Down Sweater, about 312g or the Mont Bell Down Inner (210g) or "parka" (with hood) at also about 260g.
All of these are a replacement for a heavy fleece type jacket not for well below zero temps. (the compress much smaller)
For that you go up to something like the WM Vapour jacket at around 450g.
The lighter versions have 15/20 denier fabric , so very fragile .
Here is the Flash compared with a 550 g fleece jacket. The Flash is warmer (the hood makes a big difference) about half of the weight and stored size of the fleece.
With storage sack , not included but recommended, (mine is by ID , a bit more than twice that "compressed size") is 290g.
I shove it into the sack and let it find its own space inside the pack. (IE, not compressed as in the pic...)


Franco