@tenten20 - Nice, I was doing something similar, but much more crude/simple. Basically was using a spreadsheet with a column for each girl, and a row for each day, and was putting a letter in a box under a given girl, representing which time slot I should interact with them, as well as a number for the level it would bring them up to. Though I was going at it a bit haphazard, and I had to change things up here and there because of girls ending up in the bathroom or somewhere else I wasn't expecting them to be which would cause me to have to change the schedule around.
It was still good enough to make sure I had plenty of levels with the required girls for the Sunday beach trip and the other level locked event options. It got tedious after a while though, so I'll be glad to give yours a spin instead the next time I play through, assuming you keep it updated since I'm waiting for the next update to give it another go.