Having us unable to do anything on friday (because pta) along with no option to turn off girls being added every single week is fairly annoying. You only have 4 days to make any progress with the girls a week...
I'm not as concerned with the number of students (20 as a cap is not an issue for me), but I think having 4 days becomes a serious issue because the win criterion (15 sex addicts) seems impossible now. If you have girls[0] start every Monday, then you never get to interact with girls[12] or later. To deal with this, there are several possible solutions.
1) Drop the criterion to 12 girls.
2) Drop the criterion altogether and have some other win criteria - I understand that you're planning on doing this.
3) Make the Friday meetings after exams on Friday, or first thing on Saturday mornings. Whatever is realistic enough or easy enough to implement. That would allow for 15 girls examined per week.
4) Cycle the girls: Once a girl has failed an exam, she goes to the back of the line. That way you interact with all girls. If you want to examine 12 girls per week, it may be better to have a smaller number of girls than 20 though. I think
Ninoss has implemented a version of this in their code.
5) Apply shufflegirls at the end of the week regardless of girlQueueFinished.
6) If you implement subjects (perhaps with unique mechanics such as buffs or debuffs) of some kind, each girl may have a subject or subjects that they are trying to pass, the exam for which is on a particular day of the week. So new girls will be allocated to subjects, and you would always see them on a particular day of the week, although probably every week or 2 depending on how many girls are enrolled in the class.
7) Have the option to move students, perhaps as a privilege granted by the headmaster or PTA. That way you could choose which students got assessed on a given day, or choose one student to have in the exam and the others are based on the order determined by the game. That could be used to focus on corrupting a particular student, or having a sex addict attend to make corrupting other students easier. This could be harder to implement but not too bad.
These are just options, but I definitely think 4 or 5 would be the most beneficial. Additionally, I think the "No uniform" condition doesn't work properly. Girls can wear many different upper, lower, socks, and outer and will still register as obeying the uniform condition. Couldn't see where the clothes were selected for the no uniform condition. Might have something to do with the "No uniform rules" condition and maybe the wrong condition was applied somewhere?
Anyway, all that to say I'm really enjoying the game and the modded version. Hope this gives some ideas about how you can continue improving it. Great work!