Having just re-read your excellent article, and after a year of keeping a low light tank, I see something else that would improve the article a lot. It can be difficult to decide on what plants will do well in such a tank. I found that many plants just don't seem to make it, even though I thought they would be good candidates. So, if you were to add a list of plants you have found to work well in that type of tank, that would be very good. One group of plants that would be especially useful to know of is low growing, carpet plants. You did note that HC didn't do well, as I would have guessed, but some of the photos seem to show dwarf hair grasses doing well. Do they really?
There is a big list of "low light" plants in this forum, but, unfortunately the list was mostly made when people considered light only in terms of watts per gallon. A 20L and a 20H tank are both 20 gallon, but the light that would be low light on the 20H will almost certainly be high, or at least, medium on the 20L. Any new list should, in my opinion, include only plants found to do ok with 20-35 micromols per sq. meter per second of PAR.
I'm about ready to re-scape my 65 gallon tank again (I'm bored) and I think I want to do a dry start, possibly with Aquasoil, then follow this method with the tank. So, any information that improves the article will be very helpful to me.