Here's my all sky setup - I found the mini-Benbo tripod I bought for £35 in a shop in Cookstown with a view to using it for macro work is also ideal for pointing the camera straight up, something conventional tripods don't do at all well.
The Peleng's front element could do with a clean!
Coverage does seem to be the full 180deg across the diagonals, almost as much horizontally and about 120 deg vertically. There does seem to be a flare at the opposite edge to any bright light - the Sun it this case.
So all we need now is some clear sky!
Paul.