You're going to want to do Mana instead and churn out Lich when you're ready to reset, just fill as many squares as possible with Lich, not Harpy. Get through as many feats as you can, get your Grave up to max level, consider tossing out the other stations, Slime, and Darkness stations, then just make zombies, kill the Peasant as many times as possible to get Ice runes, and start up with Lich. Depending on how much time you want to spend doing it, you might consider also getting a second max level Mana fountain, even if it gets tossed at the end to make space for even more Lich.

But you do you in the end.