Best way to properly scale text?

This is using TextMesh and MeshRenderer. There are 3 different variables at play: font size, character size, and scale of the transform. Setting one higher and another lower makes the text blurry, while setting one too high will make the text sharp but I assume at an unnecessary performance cost. If I know the size the text needs to be, what should I set the values to so that the text is rendered at its sharpest?