I’m not sure what your question is….. How to make roux or if using Zatarain’s is OK. …… I’ve made a gumbo twice in past 2 months. Everyone loved it both times. …. Anyway most recipes calls for equal parts oil and flour. I use about 75% oil to 1 part flour. My recipe to serve 8 to 10 calls for 1/2 cup oil & flour, I use 1/2 cup oil maybe a little more to 3/4 cup flour. Heat oil on medium heat, add flour an stir until golden or as dark as you like. The mixture should look thin or watery while cooking. It will thicken when boiling after adding water or other cooking liquid.