I play the Prime Mod as a female Zero with no addictions.
(I will also try the no harem setting).
It's not that difficult. a few dates Just as friends at first, love and obedience values quickly soar.
I even like to have the ladies make the first (sexual) move.
When dating, only single dates. Later, when the women get along better with each other, there are also dates for three.
I even made a list of women who are cinema-technically compatible:
I've also started making a more precise table of how love increases depending on the film selection. Had to find a save for Laura and Gwen where they aren't at 100...
There is also an opportunity to grab extra love points at dinner in the restaurant. If the question comes up whether you want to order for your date, you first say yes, and then when choosing the menu you say: Let your date decide.
Buying clothes gives a lot of points. You should save that if you are already in the middle range. In my experience, the books don't give that many points either if you're still at the bottom with the bars.
Taking a shower often helps too. The random encounters, especially when the other ladies burst in, rain points.
I also think the harem hard mod shouldn't be that hard. If you, I think it was Jean (or Emma), are caught making out in public, you can combine Jean's (or Emma's) powers with Prof. X's and make all the ladies like each other better.
However, I haven't tried it yet.
Getting Jean is quite easy.
You don't give a damn about love and put everything on obedience. If love slips into the negative area, it doesn't matter, the next time you meet Jean, the bar is back to 0. That way you get to obedience around 200 relatively quickly with her.
The hardest part is getting Jean to be friends with the other girls. Everybody hates her. Except for Gwen.
Gwen, on the other hand, is the easiest. She's a real fan girl. She loves all girls. Is a huge fan.
At least that's my impression after more than 100 hours of play.
It takes a lot of threesome sex (I mean really, really a lot) before someone (other than Gwen) is willing to spend the night in a bed with Jean and Zero.