Language Schools: How to decide on the right school?

Next month I’ll be visiting several places in Japan with the goal of checking out different language schools. I’ve been researching options in Tokyo, Chiba, Shizuoka, Hamamatsu, and Nagoya so I can get a feel for a variety of locations and school environments. I should preface by saying that ideally I'd like to land a school somehwhere outside of Tokyo so that rent/bills are more managable, I also have a fondness for Shizuoka. One thing I’ve noticed is that many schools (especially outside Tokyo) seem to have very distinct student demographics, with virtually 0% western students. Sometimes hundreds of students made up mostly of just one or two countries. As a white english speaking person, I sometimes wonder how well I would fit in socially at a school where I might be the only person from my background. I don’t mean this in a negative way toward anyone, but I do think about whether I’d find it easy to connect with others or if these types of schools would even be able to support me in getting set up in Japan as an English speaker. When I contacted one school in Shizuoka, they mentioned that in their 20+ year history they’ve never had a British student, and that they haven’t really supported students who speak English before. That left me feeling a bit puzzled about why no other Western students seem to choose this school. I come from a country with a very mixed demographic, so diversity itself isn’t an issue for me, but I do worry about whether I might feel isolated or unsupported because of my nationality or language background. My main goal is to take the risk and learn as much of the language as I can during my two years, but I wanted to ask if anyone here has experience attending a language school in Japan and **what factors I should keep in mind when choosing the best possible school. What helped you decide on the right school for you?** Is student demographic something I really need to consider, or is it mostly irrelevant in the long run?