WinUAE AmaxII and GCR disks

[MastaTabs]

I doubt its possible. Only 800K Mac disks used the GCR encoding and with them comes a major hurdle.
Apple used 5 different rotation speeds spread across the disk sectors resulting in different bitrates. So you can only read Apple GCR disks using a Mac drive with an adapter or using the Catweasel.

[MastaTabs]

Then I'd suggest to use DiskCopy inside MacOS to create .img DiskImage files of the disks.