I've gone down to 18 deg F twice like this (including this past weekend). I also had some warm layers of clothing on. I wasn't cold, but wasn't exactly toasty either. I did have the space blanket as the first layer just below the hammock. I think I vary from night to night, but generally I think I am a bit of a cold sleeper (more tolerant of hot nights than cold).
The Jarbidge, like the others have said will work on a HH just takes a little more fiddle to get it dialed in. The Potomac will fit better with less effort....but we are only talking a moment or two between the two quilts.