When Maconverter exports to the PC, it will convert it back to exactly the same set of files you started with. Since the vast majority of posted packages are PC .zip files, your Mac users will probably know how to use Maconverter anyway. So the best strategy will be to export to PC, .zip it and post it as PC/Mac. If you want to create a "ready to use" package for the Mac (without the need of your customers to use Maconverter) then you indeed have to post two packages.