HOW-TO-ADJUST (with pictures) Loader Relief Valve - Massey / Iseki / Challenger / etc

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Slightly on / off topic.

I am trying to figure out what is the nut/set screw adjustment valve looking at my Massey GC1720 deck by the mower height adjustment knob.

I am assuming this is the pressure relief valve for the hydraulic system? The one with RED arrow (AGCO calls this a Retainer Valve) What is the valve with the blue arrow (AGCO calls this a Flow Valve)?