Hi. Since the SpecV isn't super tall, I think microswords (better if roots are down in substrate) would work. Also, Crypt Parva is good (root feeder) but it likes to spread - maybe ok, maybe not for your scape. It's not traditional Iwagumi, possibly, since the leaves arent straight thin, but it is one of my favorites. I'm only suggesting easy plants, of course, and low maint. That's more my style. If you want to do some higher lighting and CO2, my advice is meaningless.