Walkthroughs for custom maps.

Harpies are divided into 6 stacks with SoD SP enabled and 7 stacks with HD+ without SoD SP.

In my opinion, this is cheating. In a clean SoD, there are 6 stacks of 25, and the wall's tick rate isn't enough if less than 8 level-ups were spent on SP from 14 level-ups. I tried to generate a save with a minimum of 8 level-ups for Luna in SP - no luck, more than 6 is not possible.
So, it's definitely possible, but it might take weeks/months.