I use a bit of both but the deciding factor is this.
Do they have any characters in the support zone?
If yes then use math.
If no, ASPIRANT RUSH
The math follows these guidelines:
How may aspirants will it take to clear the defense zone?
The correct answer is as many as you can field.
Is aoe damage a worry?
The correct is no because RUSH.
Conclusion: Heat Wave/Morale Death aka Crushing Victory.