We are kinda in the dark (pun intended) considering the true print run of The Dark
A few years later the Paris mulligan took its place, and then the Vancouver mulligan most of us know today
In other words, your opponent will know the targets of your original spell and your copy when choosing the new targets, if any, for their copy
You probably have some long boxes or fat pack boxes sitting around
There's also Smoldering Marsh and Sunken Hollow as slow lands with basic land types, and Canyon Slough and Fetid Pools as other duals with basic land types
Somewhat expensive on its own, for six mana youre going to want to be turning a good number of small tokens into much bigger flying ones to get your return on investment here, especially considering that in most situations youre going to need to wait a full turn cycle before you can swing with your new flying death squad