The private school sounds ideal. I don't know if this is a concern but is the tuition between the two very different?

We are in a public Montessori right now so it's not run like a strict Montessori but it doesn't seem to be the right fit for my son...even though I was sure it would be. Your school might be a really good fit though.

Is your reason for not sending him there because he won't be around kids his own age?