I looked at the queen as well, I thought that would be awesome but I was not sure if the maintenance requirements would be something you would want to deal with. I don't like being a pessimist about these things either, because I feel like there are way to many posts out there already that just come in and say "no," to everything without even trying to find a solution. With that being said, I want to help you find yours.
What are roughly the sizes of your fish? Do you mind if I get a picture of your entire DT and it's dimensions?