For my first test hang (report) I used trees about 15' apart. I think everything was set up fine and slept well, but I'm not 100% sure.
In my WBBB, the middle of the hammock seems to be pulled tighter than the rest. I don't know how to describe it, but it's like a bunch of channels of fabric most noticeable between my legs to the end of the hammock that wont spread out to the sides. Depending on my exact position, I can sometimes feel this under my knees. And forget lying straight since it's higher than the sides (feet fall to either side)
I usually have this problem in my Grand Trunk UL too and could never figure it out. Is this caused by an improper (too steep) angle? It looked like 30° to me, but maybe I'm closer to 45°.