hang angle WAG
Don't get too wrapped around the axle about the hang angle for now. You'll get it figured out with a little practice. For my Explorer UL I normally find two trees about 14' apart (5 paces or so) and put the tree straps about as high as I can reach. This seems to come out about right.
If you pull the hammock tight between two trees then hop in it will put a ton of pressure on the ridgeline. The lay should be exactly the same (that's what the ridgeline does) but it puts a lot of stress on everything for no reason.
One of the leaders in the scout troop does exactly what you described. He's about 250 and pulls his hammock banjo string tight but only hangs it about head high on the trees. I don't know how he hasn't snapped the ridgeline yet.