I noticed the same sort of thing with 2.5oz Climashield XP.
I was making a shaped quilt comprised of three separate panels. What I did:
* The layered nature of Climashield make it pretty easy to separate the layers to make thinner material
* I separated scrap pieces and layered the resulting thin pieces over the thin spots
* The three panels resulted in 4 lengthwise seams (the two edges the two more through the middle joining the panels. That provided enough seams to stabilize the patches
That resulted in a slightly heavier quilt (just a couple ounces) but the temp range I’d like it to handle seems to fall between what I’d get from 2.5oz and 3.7oz so they are a welcomed couple of ounces. Night time temps here are just starting to get in the range needed to test the outcome.
I’m sure the technique would also work well for folks making clothing articles. I’m not so sure how it’d work for a single panel quilt.