How to read Amiga 880k disks on AppleIIGS?

[Oldsmobile_Mike]

I don't understand what you're trying to do, but if you just want to transfer files all three machines should be able to read PC DD 720kb disks (with appropriate software).

[Oldsmobile_Mike]

So, I can format an DD 880k disk to a 800k disk on the Amiga?

Possibly.  With Shapeshifter.

If I understand correctly, you have some Apple IIgs disk images on your PC.  And you're trying to transfer them to the Apple, by using the Amiga as an intermediary?

As an alternative, would it be possible to zip them on the PC to something small enough to fit on a 720kb disk, then transfer them directly to the Apple, and un-zip them back to 800k size and write them onto disks that way?  Thus taking the Amiga out of the equation?

AFAIK the Apple should have no problems reading PC double density format disks (720kb), with appropriate software.

You might have better luck asking this question on an Apple forum, I'm sure people there ask "how to transfer from a PC" all the time.