Please, the fact that you are asking this question worries me.
If you do not know what you are doing, you can damage the system.
It isn't as simple as just filling the system.
If you have to put refrigerant in, then there is a leak. Putting more refrigerant in isn't going to solve the leak.
Another thing to think of. I have seen dozens of people buy these garbage kits, fill their system with it and have the compressor seize a few weeks later.
Why? Because along with the refrigerant leaking out, the oil that lubricates the system often leaks out along with it.
It's your vehicle and you can do what you want, but if the system is repaired properly, it may work for many years more. Your call.