If you do what you are proposing you will be breaking one law, a Federal law, for sure and possibly be breaking state law also.

To begin with it is mandated by Federal law that any system that is charged with a particular refrigerant has the appropriate adapter fittings for that refrigerant. You're messing with the Federalies here. I'm not preaching, it's your business, but I want you to be aware of what you're doing.

Secondly, duracool and other explosive refrigerants are against the law in 18 states and the District of Columbia. I don't know if Rhode Island is one of those states or not.

You would be MUCH better served to stay with the original refrigerant, or if you MUST convert, use nothing besides 134. The snake oil refrigerants such as duracool are everywhere and they are causing many problems for many people. They are contaminating our remaining recovered R12 supplies and they are causing much woe for the hard working people who are trying to earn an honest living repairing automotive a/c systems.

Please do everyone a favor, mostly yourself, and use 12 or 134.

Good luck,