I agree that the leader hose should be the first item attached to the output.
Makes sense because of heat. Unfortunately I’m committed to my redesign with the check valves mounted to the heads. AZ has it that way so I stuck with it. The new ones are good to 180 degrees.
Kingvinnie - thanks for the extra pics of your install. I like your style - it’s all very tidy. Do I see some POR 15?