As far as plans like in a schematic, no. I just copied a store bought unit, increased the size and added a fuge and 2nd sump.
I'm using the bio balls from the store bought wet dry in the mean time for their good bacteria. There is a small strainer on top where the water returns from the tank into the wet dry area. After the tank settles, this will be replaced with carbon and the bio balls will be replaced with a baffle box.
No pre-filter from the overflow box (which I made also). I changed the design up a bit from what was pictured. I did have it drain 1/2 to the fuge and 1/2 to the wet dry. It now drains directly into the wet dry via a 1.5 through the back durso. Water to the fuge is diverted from the sump to the skimmer sump. It is skimmed then flows through the fuge back to the sump slowly and can be easily regulated. I'm going to run it this way for a while and see how well the water does. I may move the skimmer pump to the main sump and use the output of the skimmer to flow water through the fuge. This will alow me to use more of the mag-12 for flow from the sump to the tank. Not that I "need" more flow. I have a 3600gph Sequence closed loop.
The filtration goal will be the plenum fuge, rock rubble, protein skimmer and of course live rock in the tank. All other mechanical filters will be gone.
Rght now the tank is stabilizing and I have 40lbs of reef sand for a SSB in the tank. Fuge has 4" or so large aragonite set up Jaubert style plenum.