how tall are the 5 gal.I think the 3 gal would work good for your setup. I think they will take about the same sqft as your 2 gal so it shouldn't change your plant count to much just add some additional weight to your plants.
i been lookin and see thier called airation pots .few companies do them.i'm big on hydro-farm stuff.my temperature cotrol heat matsmare hydro-farm.i like my 1000 watt hood, yield master 2.its kinda thin, long and wide, my 600 is a lumatek.hell i might do the 5 g.5 gal smart pots are 10 1/2 in tall and 15 in wide 3 gal smart pots are 7 or 8 in tall and 11 in wide. I don't know about other companies pots as I don't have any. And the ones at that hydro store are a different company so you would have to look up the specs on that brand to know.
i'm gonna switch and order some same time i order my beans.Essentially, air-pruning is a technique that stops root growth extending beyond its growing media by exposing the roots to relatively dry air (as opposes to getting bound up and wrapping around each other like in a plastic pot).. the roots will grow through a smart pot and out the side of the fabric pot, reach air and then stop growing. These primary roots that are air exposed have nowhere to grow The plant will stimulate an abundance of secondary roots to branch out. These secondary roots will then spread through the medium until they get air-pruned and then stimulate more root growth. The overall effect of this growth and pruning cycle will create a plant with a well developed root system. This causes an explosion of plant growth. I myself am experimenting with Smartpots right now. I have a friend that says it is all he will ever use from now on. I also hear Air-pots work well.