Alright, so there's a minor glitch in MSE when you emulate it through Wine (or, at least, I've run into this repeatedly): drop-down menus don't work. At all. Now, this wouldn't normally be an issue, but this includes setting cards' rarity.
I've spent the couple of hours fiddling and I've managed to force cards to show the right rarity symbol (I added a new styling option and had the rarity field ask that for what image it should be showing), but that doesn't change the underlying card's rarity (so they aren't autocounted or autosorted, and randomly generating booster packs doesn't work).
And, on top of that, running the following via the console: set.cards := "uncommon" // Or whateverdoes jack and shit - it fails with a "(22) can only assign to variables" error, which isn't exactly helpful.
So... anyone know how to do this programmatically? It'd be a great help if you do.
I will be battle-boarding soon. I think. But, like, in a new way.
But seriously, though, consider giving Battle Boards a try.