32 oz based on an empty system.
If you didn't evacuate the system who knows how much you need. You should have, at the very least, a set of manifold gauges to be able to tell what you hi and low side pressures are.
Why are you charging your system?
Do you also need to add an oil charge?
FYI, if you overcharge the system it will KILL your mpg and the efficiency of your A/C will be terrible.