Originally Posted By: rooflessVW
Pretty much. Use the oil type specified by your compressor's manufacturer and the refrigerant you're using...
Oil qty has a far greater performance impact than oil type. As quoted above, use the oil the compressor manufacturer specifies because they really do know best. It's all about proper lubrication and seal compatibility. Also, it's actually very difficult to fully change unless you have a recirculating flush machine, and very few people have those. Get the refrigerant compatibility wrong and you get sludge and/or acid and it becomes a very expensive repair.
Not really something to be futzing with unless you really have nothing better to do, money for tools and time to make sure you get the compatibility right.