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2% is the correct mixture of AC Fluid. No more no less. More is
DEFINITELY not better!
Use common distilled water. My suggestion is make up a 2% mixture based on the size of the AC fluid bottle you have. Any extra mixed solution can be capped off and used to top off your system as you lose coolant.
The other option is to carefully measure the exact amount of distilled water added (in CC's) to charge your Aquaduct. Then add in a enough AC Fluid (use of a syringe graduated in CC's) to give yourself a 2% mixture.