Good job, JayT! I'd hit that! How did cooking the rice in the gumbo work out? Not too starchy? And yes, file' is a thickener.... gotta b e careful or you can turn the whole pot into a slimey, gooey mess. Looks like you managed it just fine, though. Ground sassafras used properly.
I've always approached chicken or turkey gumbo differently than seafood.... chicken gumbo should be thinner than seafood. I usually make my seafood gumbo with a darker, heavier roux to thicken the gravy.