Best way to make a draftable Custom set on mac for Cockatrice?

[Lurker101]

Hey all,
I've always wanted to take part in a reject rare draft and wanted to host one on cockatrice. I didn't want to use a cube format because I wanted multiple copies and Sub-rarities for the rares. That type of regular draft format for Reject Rare just seems more fun to me and allows me to put in more bad combo cards than a cube would. So ideally it would draft like any other set. I can't use Magic Set Editor because I have a mac. Does anyone have any ideas on how to do this? Would I have to make an .XML or is there another way?  Thanks in advance for any input and advice.