Well, this thread is fairly old, but I simply have to reply. It seems the OP is concerned with the ease of reading the labels, needing to get them at the right height. Sun fading inks is a big problem.
I use pieces of Aluminum cans, cut with rounded edges, and a hole punched with a paper punch. I can put the variety, date I set them, or other information into the soft metal by scribing with a rounded metal point. I actually use a 60D nail wrapped in twine with the point filed smooth and coming to a dull point.
Since I have dozens of old electric fence posts, I use them as stakes. They're around 5/16" thick and 3 feet long. Using the old electric wire, I wrap the wire, split ring fashion, around the end of the post and again to hang freely. Then it's a simple process to slip the punched hole through the free spiral.
Stake in front of some lettuce I have under plastic
detail of the fastening.