Not at home so cant provide pic but I had similar problems with a dual burner setup for my crawfish/ shrimp boiling rig. Because of the different burner designs, one wide open and one restricted because of flame disk, I came to the conclusion that it provided too much back pressure to the regulator. I teed at the tank and put 2 separate regulators with 2 separate needle valves for burners to run independent of each other. Solved problem immediately for me.
Good job by the way. It looks great. I am in the process of building a similar rig with exact same size cc. Might have future questions for you. Hope I was some help to you.