dont think you can use metal especially if your doing salt water. i just wrapped it then held it down with the gravel, or like you said put the tail on the bottom
The skimmer box had about 4-5 sponges in it. I do think there is a filter in the stand, and the man I got it from called it a sump. Once I unscrew the vent on the other side I can get some pictures.I would not invest too much into it. Your lobster tank does not have a bio filter because of the ozone. The false bottom is must likely feeding into the skimmer box. Since there is no filter under the stand, they most likely have the skimmer box rigged with some kind of mechanical filtration. Is there a cartridge or floss in the skimmer box?
The Little Giant pump is sucking water from the skimmer box and returning to the tank in two places.
I personally would put gravel in the tank (bio). The bottom appear strong enough to support. No additional grating needed. Cut the in and out to the chiller and connect the two hose together. This allows the water to return to the tank. Pictures inside the skimmer box would help. Make this your mechanical.