Same issues as the other thread IMO....
In these super low loft applications I think the down is just too fluid and there isn't enough space to do it's job.
https://www.montbell.us/special/products/plasma/
This is an innovative quilting pattern... but still. 3/4-1" diameter clusters in 1" chambers. Maybe in bone dry conditions where a quick sunning per day would revive it... if you were really pushing the grams.
FWIW- the shell won't protect you from your own body or from environmental humidity. Only a full WP shell would do that.
I won't be going with an UL down jacket again... too easy to beat up, singe a hole or wet out for me.
FWIW part 2-
When I take a down vest it is my safety piece... it isn't designated to work in any portion of my kit or counted on. It's a bonus.
I agree it would do more for my torso most of the time... there are a few times you just have a trouble spot (elevated feet in a hammock, a cold shoulder or hip, a bit too much draft in a tight quilt when pushing the limits of it's rating) and that's a good catchall piece. Also if I was ever in real trouble- it's a piece I can wear backwards with my pack on and walk my way out with the extra insulation.
And best of all... if I happen to find myself with pleasant company and a fire; well I can always stay outside my bag and wear it as an actual vest!