If you don't have it already, go grab Apple Disk Transfer (ADT Pro) and a serial to USB adapter to connect your Mac to your Apple II. This will allow you to write disks on the Apple II from image files stored on your Mac.

It won't help with your //c but if you have an Apple II with a cassette interface, ADT Pro also has the option to output data through the Mac's audio line out to the cassette interface in lieu of a serial cable.