Brian, I want to overbuild my system. You can never have too much filtration or oxygen. If you have the means to add, then why not?
I'm not nearly qualified to answer those questions, but my gut feel is that at some point in overstocking (who knows? 2fish/5gal, 3? 5?) the filtration becomes a secondary effect to cannabalization, fish stress, susceptibility to disease, whatever. If you're still well clear of that, then keep on keepin' on.
Wow, they are sure growing away. In my hydroponic system I use rock wool, but what you use is reusable. Look forward to updates.
They are in there but it's hard to take pictures. They are too small. In a couple months, they should be big enough to take pictures of.