In large soup pot over medium heat, warm 2T canola oil. Add chicken and saute, stirring occasionally, until cooked, about 10 minutes. Season with 1T Cajun seasoning, S&P. Transfer to a bowl and set aside. Return pot to heat and add remaining oil and whisk flour to create a roux. Cook the roux until golden brown, stirring constantly with a spoon. Be sure not to let the roux burn. Add the onions, peppers, celery and okra and cook stirring occasionally until softened, 8 to 10 minutes. Add chicken stock and remaining Cajun seasoning, sausage and chicken and bring to a boil. Reduce the heat to medium-low and simmer for 30 minutes. Spoon rice into bowl and top with gumbo.