Curious

I've been meaning to read the doukyuusei mangas (I watched the movie so long ago but I loved it a lot) and I'm finally getting it but I was wondering, from those of you who have read the whole manga, story-wise would I be ok to not read Sora To Hara? I will be honest I don't care for the teacher and I don't feel like reading abt his crush on a high schooler. I assume I am not the first nor the last to not want to read abt him but I was just wondering if it had anything major abt Kasube and Sajou that I'd be missing cause idk if I'd be able to push through it even for important details on them.