Your question is analogous to asking what size shoes should I put my son in for him to grow full sized? Larger pots do NOT make plants grow larger. Optimizing light is the key determinant of plant growth. Only after a plant becomes quite potbound should it be moved to a new pot ONE SIZE larger. It is a gradual process. Focus on keeping your plant healthy, not growing it ever larger. Hypoestes is not generally a large plant to begin with.
