YFuse Pertex fabric

The d or D stands for denier, which is a measure of the weight of the threads used to weave the fabric, and roughly (but not always) correlates with the weight of the fabric.  It is the coatings that affect vapor transfer.  So you were right to steer away from the PU coated material.  There are so-called DWR (durable water repellent, but not water resistant) coatings that will bead a small amount of water before leaking, but they vary with respect to vapor transfer.  (Note: We have had some bad experiences with Feathered Friends.  Montbell spiral down bags are reasonably priced, and were reviewed here when they first came out.  I got one, and have never regretted it.  Western Mountaineering has some excellent down bags also.)

I have the flicker with fabric generation prior to yfuse (schoeler nano?).  I love it, ZERO issues, well built, no loss of down, laundered well.  I even got a geoduck pillow from them (5 stars)

From the pertex site.

“ Pertex® Y Fuse fabrics use yarns with unique Y shaped filaments. These filaments create tightly interlocking structure, which improves the downproof and water beading properties of the fabric. This structure also means that Y Fuse fabrics remain highly stable over extended wear and washing.”

i have a Katabatic quilt with this fabric.  It’s an update to the prior Pertex Quantum 20d.