One night my 0* quilt wasn't quite toasty enough so I tossed my Sitka Gear Kelvins on top of it. Problem solved. Sometimes ya don't need to add weight & bulk. I prefer gear that can serve double duty.
Yep, use the 0 degree for everything. A couple years ago I tried a 20 degree lighter weight quilt during July on an Xlite pad and froze. Sold both and just use my 0 degree with Xtherm for everything........except winter.
Wish I would have read this yesterday! HaHa. I have a 0 quilt that I got last year and a 20f slick bag that I’ve had for 3.
This year I drew a NM 1st archery season tag in the Gila wilderness - all backpacking- so I wanted to cut weight by using the quilt (-3.5lbs) but I was sure I’d sweat to death in a zero bag with night time temps only in the low 40F (even tho I sleep cold). I literally picked up a barely used 20F quilt last night and read this thread 1st thing this morning. Oh well!