I am in the process of dividing one I just bought for this purpose, I'm so excited. The only issue I have with it is that it's so tall it looks kind of odd.
Originally I was going to divide it 11 ways, taking 2.5 gallons each into account. Then I realized that wasn't much space width wise, so I was going to give 5 inches each - this also looked too small! I finally settled on 8, this will give 6 inches of room width wise.
I used 50 lbs of gravel so far, but need another 25 lbs. I'd like the gravel to be 3-4 inches so that it isn't quite so tall. I'm also ordering tall live plants to add in, so hopefully with all of that it will look nicer. I will also need to order a couple more sponge filters. I currently have 6 - will need 2 more.
So right now I'm waiting to go get more gravel tomorrow (w/o a vehicle tonight) before I start to fill it!