Hi there
I've had the DD Travel hammock on which I've added whoopie slings... here are a few of my findings after over 25 nights out so far this year in all kinds of weather, here in France, from very hot & humid, cool and misty to torrential rain storms. (Yep we've had it all this summer).
1) Despite what I have read about condensation in this hammock, with a thermorest mat in place I've had hardly any condensation at all. Some around my feet from time to time..(but my bag it has a sewn in nylon foot box for use with shoes). I use a centre zipped military bag turned over quilt style... works well and is warm. Note: I always sleep dressed, usually my Kiwi trousers with a T-shirt and fleece.
2) I use the whoopie slings and 1 inch webbing around the tree, with a marlin spike hitch to attach the whoopie. I spent two nights last week where it rained heavily all night. Not one drop of water got near the hammock. The water ran down the straps and was diverted by the toggle and marlin spike hitch. Also there is the excess of the amsteel after the bury where the chord is tightened, that again diverts rain down to the floor.
The amsteel soaks up no water so any excess runs off... the webbing does take on some but is close weave so again most runs off, in this case to the ground.
3) Finally on the set up, I try to make sure the toggle sit just under the tarp, so no water hits the whoopie direct. As I say been dry all summer.
Most comfy camping I've ever done.
cheers
Gareth