I have made some minor tweeks - very evolutionary:
1) I welded a disk into the opening of each pole to close off the end (the disk is the same size as the hole, not a flat plate).
2) I then cut-off the inner pole to fit inside the outer pole and be about 3-4 inches shorter to fit beneath the pin on the outer pole which locks the whole thing together. This aids with putting the foot end higher as well.
3) Instead of cutting the poles shorter, I drilled additional pin holes every 6 inches (5.5', 5.0', and 4.5'). I can then attach the anchor cords and the hammock at a lower position, but still have my tarp at 6' so I can basically stand.
4) I painted the poles green so they don't stick out so much and the booms and pins bright orange so they do stick out more.
5) I made my pins out of double-headed nails so they always stick out both sides. I also drilled some holes in small magnets to thread the pins through so that they hold themselves in place without sliding out.
6) I bought a piece of pipe insulation to put around the rig so when I can attach it to my bike or put it into the boat, it has a little softer feel. It can easily be take off when I don't want it.
As far as sand goes, I think the pole driving into the ground and the stake pulling are the two biggest concerns. Using a board will solve the stakes sinking.
I think in anything but the loosest sand, the booms will hold, but I haven't tried them in sand yet. I definitely want to try it and, given soft loose sand below, the cost of failure is definitely low.
I had the thought that they could be reversed - pipe into the sand and anchor cord attach to the stake. Though I am not sure how I would keep the cord from slipping off the stake yet.
In very loose sand, I would probably revert to tieing to a buried stick as a deadman.