It's fun to read, feels like a sports manga but... something about it still feels off? Something about the storytelling isn't compelling for me (personally).
Anyway, do these kids no have to go to lessons? Is it just how the Japanese do their club activities? I get that practising together in an orchestra is important, but what about their individual studies?
Has Saeki just completely given up on solo competitions? That alone would need hours of practise outside of the orchestra, and then there's school studies too.