Yep, slept out last night. Got to lows predicted. 38/39. -- no wind. I wish I had a temp. guage so I could compare inside and outside temps, but as far as I'm concerned, AE's top cover is worth its carry weight. Definitely warmer inside. I had the cover on fully, no vent holes. Underquilt was JRB No Sniv (DIY overstuffed, now 25 oz instead of 21 oz). No pad. My WM Summerlite as TQ, hat, warm up pants and long sleeve t-shirt. I did not need to open to vent. Still need colder temps to answer that all important condensation question.
So my insulation weight last night was 19 oz for SL, 25 oz. NS, 5.4 oz topcover = 3 lbs.
Thanks for the update HappyCamper, Glad it helped. I have been looking for a good thermometer to help get a better feel for how much these are going help. I think I found one that will work but have yet to get it. If it's any good I will post all the info for them.