I see that you at Columbus GA with hottest day temp around 75F at 3pm (this from Google). This is important as you should refill the system during the hottest ambient temp.

For R134a the switch makes (ON) above 45PSI and OFF below 29PSI. It seems to me you're using some kind of gauge there. Choose the hottest time of the day and open all the car doors while doing this. Keep on refilling until the AC runs steady around 35PSI to 40PSI. Steady means no cycling - compressor clutch ON all the time.

When AC running steady you should also feel the AC tubes going into and out of the firewall (to evaporator in cabin) and they should be at around same coldness/temperature. If the inlet tube is colder than outlet you can add little more refrigerant until they're about same. But this only works if the orifice tube is within the engine compartment. Some earlier installations have the orifice within evaporator so this method won't work. So check first where the orifice tube is before using this method.

Mind you this is not the proper way of refilling the AC. It should be refilled by weighing the R134a in - gas tank on a digital scale. Proper amount of refrigerant is important as it also carries the oil for compressor lubrication. Thus undercharging may cause compressor wear in the long run. The R134a weight should be stated there around the engine bay. Proper R134a weight is also important as it would lead you to troubleshoot elsewhere if the AC still not cold.

Regards,
Amarin.