I also used to get very sweaty using a thermarest on the ground, so maybe the problem is me, not the hammocks! Most mornings I've been able to air out my bedding, but if I was doing a multi-day walk, or it was wet and miserable it wouldn't be possible to get stuff dry.
As far as temps go, mostly around 5-10C. It's happened in both high and low humdity which makes me think maybe I'm overheating as Youngblood's post says. Trouble is, I'm not awake to know it and do something about it.
2Q, thanks, yes I'd read Youngblood's post previously (I was one of the ones who needed it!) and I'm still not sure I fully comprehend the whole thing.
I'll acquire a CCF pad and try that to see if it helps, or try not using a VB until it gets down to freezing. Colour me confused (and moss green)!
Thanks all for your answers.