There isn't a very in-depth modification.
The basic steps were:
1. Locate where I wanted the third attachment point.
2. Sew on the third attachment point on the underside of the tarp.
3. Relocate toggle so it can attach to the new attachment point.
4. Attach paracord or some other cordage to the head end attachment point. (above tarp)
5. Run cordage down to foot end, through some sort of pulley, then (under tarp) back up to the head where you can reach it while in your hammock. I made my pulley out of a deer antler, so the paracord had a nice smooth and wide surface to glide on.
6. Attach shock cord or surgical tubing to the head end attachment point.
7. Attach the other end of the shock cord or surgical tubing to the ridgeline or your hammock tree hugger. This part depends on length, how far you want to stretch it, and how far it will let you stretch it.
I know that a list of....attach this, go here, do this, etc. does even compare to some of the diagrams on the forum, so if someone is so inclined i'd love to work with you on making one.