I say trousers and nice kilt option for all
Yes, I think that sounds perfect too. Although, I'm actually a big fan of no uniform at all since my kids started at a school like that.
At my all girls school, in summer it was probably 25/75 trousers/skirts, but come winter, the vast majority of us did the switch and wore trousers - because why wouldn't you. I don't recall us all looking terrible, we all managed to find some kind of trousers that fit the strict standards
I think it's the culture of the school that determines how many girls wear trousers, because at that girls school, I don't recall any comments at all, but when I moved and went to another school, the vast majority of the girls wore skirts, and I remember lots of policing comments from both the boys and the girls.