On 80 stamina map I got 410 currency per run. And due to the new event daily quest, you must do the 40 stamina map at least two time. It give almost the same currency than the 80 stamina map and complete the related quest, giving you 60 more currency per day.
But yes, it's just farming, farming and farming again.

Oh guess I should stick to the default placement then, even if it means leaving one pest alive. Didn't notice that I'm missing one item because the squads can't open the padlock after the mission is over and just keep running in circles >.>