New construction window parapet height for guest bathroom

At least I don't find it nastier if I'm not the one getting sprayed (and I can just put the lid down if I want to). How do I come up with that? If you have to put the lid down before flushing, you have to lift it again after flushing to brush or at least check the toilet. For someone who's not really used to doing that, every additional necessary step lowers the willingness to do it. That's true in every area, not just toilet brushing. Also, it's hard to flush while brushing and then the shit stays in the brush, which I also don't find very pleasant (this problem can admittedly be largely solved with silicone brushes. No idea why they haven't become more widespread yet).