55g FW Sump

[Rumble Fish]

So, as part of my 100g freshwater tank project, I want to incorporate a 55g sump.    Basically my plan from left (where the water enters the sump) to right (where it is pumped back to the display tank) is to have a wet-dry filter area with filter floss and pot scrubbers / baffles / a larger, open area in the center to grow live plants and install the heater / baffles / then the pump.  I also want to incorporate a Hamberg Mat Filter (HMF) into the design.

My question:  would it be more effective to install the HMF just after the wet-dry filter or just before the pump?  

My thoughts:  If I place it just after the wet-dry, the mat has access to the highest bio load which hopefully translates into a healthy mat.  If I place it just before the pump then it then it has the least access as all the mechanical and biological filtering is before it but the plants should be healthier. And, if nothing else the HMF will provide a clean polish for all the water passing through it.

I tend prefer slower growing medium light plants (java fern, crypts) in general, as this usually means less maintenance but now that I have a larger tank I'll definitely plant some swords and vals also.  My sump tank will house faster growing, unrooted types strictly for biological filtering.  However I plan on adding these after the display plants are growing well and the fish population warrants it.

I'll keep adding to this post as I get closer to finalizing my ideas.