I'm interested to see how this experiment will work out. However as I learned recently there is much more to filtration than volume of the biofilter, "good" flow through the filter, and aeration.
Here's a Dutch website that talks in depth about many things planted tank including filtration. I am seriously thinking of translating the pages and posting them to the DFW aquatic plant club website. If you put the effort to translate you will read things that you have never seen on an English speaking forum. The Dutch indeed have ways to run a true Nature aquarium. One example is fine tuning the nutrient ratios by adjusting the feeding + water flow through the filter + the biomedia choice. Another example - raising a nutrient level by collecting algae from the tank and placing them in the filter where they die without light and release the nutrients in the water. http://members.multimania.nl/brieneo.../startpag.html
The website is hosted for free and it has heavy banner advertising. The advertising banners do not let me scroll down a page. The only way for me to scroll up/down is to highlight the text and move the screen down by highlighting.