I got the tension and foot end higher tricks from Brandon's recommendations for the BlackBirds. Can't take credit for those, but thanks anyway!
My Hennessy came with shock cord for the tie-outs (I think all of them do; at least, all the ones I've seen in person do), but I only bought it about a year ago.
Mine doesn't seem to sag quite that much, but it does some. I mean, it is made of nylon, and that stretches. The suspension doesn't, but the hammock body does, probably two to four inches overnight. I don't let it bother me; I just make sure that I'm at least six inches off of the ground before going to sleep. Part and parcel of having such lightweight fabric, I suppose.