I don't get much, if any, liquid when I'm removing the oil from mine. I just spoon it off. Comes mostly from the sausage/andouille. Gumbo is always better the next day, but I've never put it in the fridge to harden the grease first.
The advice on removing the fat from the stock before using it is good.
Using a dry roux is not the answer. You're going to have fat from the sausage unless you use that and you shouldn't have a bunch of oil from the roux unless it separates.
This post was edited on 11/15 at 2:05 pm