You guys are cracking me up. Serious LOL going on here!
anywhere as long is it's submerged is good. Can you ever have too much filtration? Doubt it.
Bioballs, even when submerged, don't have anoxic zones so they don't help as much. Some of the newer products do seem to have crevices in them so they may be able to take the place of LR
I think I've heard that even with bioballs some folks have zero or near zero nitrates. A good fuge with lots of macro would help in that regard as would some other methods of nitrate reduction (denitrator).