Another option, as above, is to compress the ADF with GZip to make an ADZ file. You need to make sure the program you're using to unpack/write the ADF to disk can support this though. (I use Codetapper's diskwiz). (Diskwiz can also write zipped files, although I haven't tried it out.)
An alternative is to use AmigaExplorer and a null modem cable to transfer the files from your PC directly to the Amiga's floppy.
