Still a newb. Just set up my new MacCat Standard (which seems great by the way). Based on your advice I hung the tarp directly to the tree. I've got my hammock as tight as I can make it, but when I get in it, the hammock drops almost two feet below the ridgeline of the tarp.
My hammock is still new - I haven't slept in it yet, but I have layed in it a bunch. I suppose I've still got some stretching going on, but it seems like I'll have a hard time keeping dry if I am giving up two feet of coverage.