Not sure where you're planning to hike, but just for some comparison, I used a Western Mountaineering "Aspen" 25° and a silk liner last year on the JMT in September, and froze every night except maybe two nights. For reference, I was using a Large NeoAir with a Gossamer Gear "Thinlight" pad underneath. We were in a Six Moon Designs "Lunar Duo." I'm 5'7", regular build, my friend is 6', thin build (she used a 40° WM MityLite and silk liner and also froze.) I had on my Patagonia down sweater, and most of the rest of my clothes on every night (made for a very thin pillow.) The worst part was that I couldn't keep my feet warm--I was to the point of tears one night. It did snow on us the first couple of days, so it was pretty cold, but it was the last couple of nights that were the worst--around Dollar Lake and beyond.
So, if I were to do it again, I would bring a heavier sleeping bag, I should have taken my 15° WM "Ponderosa." The hiking was fine, it was sleeping that was the toughest. When you're cold, it's not easy to sleep. And it wasn't due to going to bed hungry. We took 1-1/2 lbs. of food per person, per day, this was too much food. All FBC style, just boil water for meals, soups, ramen, mac & cheese, etc. My favorite meal was when I had Cap'n Crunch and Nido milk for breakfast. Not sure why, but that was the best. I gave away so much candy and snacks to very happy hikers. I will do 1 lb. per person per day next time.