Watch this video - in particular around 1:56 and realize that this is what most every AC shop is doing rather than emptying and recharging by weight if the AC system is just low on gas.
Again - how do YOU know that system of yours is low on gas if you have such an aversion to using gauges and P/T charts and the known ambient temperature? - IOW why do YOU want to add refrigerant NOW?
Again - how do YOU know that system of yours is low on gas if you have such an aversion to using gauges and P/T charts and the known ambient temperature? - IOW why do YOU want to add refrigerant NOW?