Mike, that's interesting. I was just composing a post to ask if anyone had experience with a Nunatak 55" quilt vs the 52" Katabatic's. I'm almost exactly the same size as you(5'10, 175lbs, 41” chest 32” waist. I'm also of Scottish descent on my Dad's side.) I have a Specialist, and have found the 55” width more than adequate to the point where I felt I could lose 3” if it saved weight. I also at one time owned a rectangular JRB Hudson River that was 48” wide, and found it fine for it’s temp rating (40F) but would have wanted something a bit wider for anything colder.
Based on those two quilts, I really though 50-52" width would be the ideal compromise, weight and coverage wise. But I keep reading people criticizing the coverage of the 52" Katabatic quilts. I do tend to flip from one side to the other a few times per night but have been training myself to back-sleep when out in the wilderness. Bringing a Ridgerest vs my NeoAir is helping reinforce that habit.
I was planning on getting an Alesck in regular when they came back in stock as I could really use a 20F quilt and it's competitive with the Nunatak Alpinist in weight, temp rating, but w/o the 6-8 week wait, and $90 cheaper.
Is quilt useable shoulder girth measure in a standard way? I’ll go home tonight and pin a sheet at 52” to see if it fits. I’d just been assumed all along that based on my experience with the Specialist, losing 3” width would be fine.