I'm sure this is an ignorant question, but what do you need diskcopy for again? Is it that you've downloaded a disk image in diskcopy format and you want to boot the emulator from it? (To run an installer or whatever?) If it's a DiskCopy 4.2 image all you need to do is strip the header off it and Basilisk II will be able to use it.

Here's some tools for stripping off the header, assuming you don't want to use "dd" for it. (or are using a Windows box.)