No no - not complicated at all: I just made it sound that way. Basically you stick a barley inflated inner tube from a child's trike under the 5's. If you have an open frame obviously you need something to sit the tube on eg a bread board or in my case a plastic chopping board. BTW I tried Herbies Big Feet and they aren't as good as the inner tubes with my open frames.
BTW I admire AS's design skills but feel is completely mistaken about the importance of amplifiers/cables/stands etc. It's hard to make Harbeths sound bad but equally hard to make them sound outstanding. At least IMHE.