Personally, I went through all the idle. Concentrate pumping need 2-3 girls. Here, the level loses relevance too quickly to pump everyone. You need to choose girls for the style of the game (I chose Idla to deploy the game every half hour, turn on skills, upgrade girls and minimize the window again for half an hour), or for Charms who are more pumped.
If you play through Idle you need to pump Bunny and Estelle (ideally Felicia and Megumi). For clicks of Mizuki and Estelle (ideally Spring and Megumi). The game should not turn off or restart as long as possible. At the end of the timer, use skills. Rebooting or turning off the game resets all code miscalculations and slows down progress very much.
Forget about Reset and Charms, there’s not enough time for them.
If nothing has changed in the last 12 hours, then it should help.
I’m sure there are more effective strategies, but I don’t know them, I went through everything described above. The only thing when you play is to switch between the office and the event, perhaps a bug will work in which the skills will continue to work after the time has passed. Whether or not to use it is your choice. Considering how much I went without knowing about the bug and the presence of many others, blocking or resetting the account will be a very rude gesture from the administration.