Thank you for posting the link! The idea makes a lot of sense and looks easy enough to implement. I would think if one were using 5 gallon containers, placing them on wheels may not be a bad idea in case one wants to move the buckets around (inside/outside greenhouse, garage, etc.).
I built some a few years ago and they're great for tomatoes. I was inspired by http://www.globalbuckets.org.
Like them, I linked serval buckets with tubing. Water one and all get watered! The last one in line got an extra tube which was my overflow.
No need to make a wicking cup. I just used the pot the tomato came in.