Man I love gumbo! Probably make it once a week or so. Okra definitely thickens it. I've never really fooled with the file'. Always understood that back in the day it was used as a thickening agent when okra wasn't in season.
I like a dark roux. Has kind of a nutty smell to me.
Your gumbo looks awesome!!! :)
UDS, mini wsm, 22.5" weber kettle