That looks great, I have the same tank and I have been looking at replacing my sponge as I feel as though it is just really accumulating nutrients if it is not often rinsed.
I am looking at getting some upgrades in the back of AIO as I am having some algae issues. What skimmer do you currently use again, is the ice cap one? And I do not have any experience with 3D printing but I would be interested in getting one of the chamber baskets you have. Keep up the good work and I enjoyed following your tank!
The skimmer I'm using is an Icecap K1 Neo skimmer, its the smallest I could find and it works well! I admittedly haven't used it in a little while because I was tired of fiddling with it though.
I can make you a filter floss tray if you'd like and are in the states (shipping overseas can get real expensive lol). I have a few colors as well depending on what you're looking for. That orange I printed it in doesn't glow overly well under reef lights but the green you see on my overflow is pretty bright under blues.