1/4 turn counter clockwise from R12. POA should not pulsate. your looks bad.

Is there air flow coming out of the vents? Is the evap freezing up? Put a monentary switch in the clutch circuit and manually cycle the clutch. Will the vent temps return to normal? Evap could be plugged.

I agree it may be low on charge. The most common problem is proper charging and it is the easiest to check. Once the charge is verified, then on to other causes.

Never tried them

I do not use Four Seasons anything. Their compressors did not hold up and that was enough for me. I do not even try their evaps or condensers. Did this vehicle at one time have a dual evap system?

older Fords are know to have defective cycling switches

Depends. How hot was inside vehicle when first started? How long before you checked temps at vents after vehicle started? Was vehicle in the sun before vehicle started? What is the blower speed? Was vehicle moving when temps were taken? Was vehicle at normal operating temp when temps were taken? Rpm...

Photos would help answer your question. Is the updated POA an eliminator type

Make sure your low side gauge is zeroed out before you adjust the valve.

Do not use superheat or subcooling in MVAC. The compressor speed changes and superheat will also change. Throw those readings out the door. These readings are used in stationary refrigeration because the compressor speed is constant. Get a new belt on there and check the idler and pulleys. Also, dis...