Thanks, it's starting to grow on me too. As for planting, I'm not sure how that would work since the area is so small. Other than moss, I can't think of other good options:
HC - no CO2 planned, floaters would reduce lighting
UG - bad news for shrimplets
Riccia - too many people say it's a real pain
DHG belem - wouldn't look right
HG - same
There isn't even from for normal squares of moss on SS. Still thinking about how to approach that one. Aside from the usual moss accents on the rocks themselves, of course.