Use the 3th person model for scaling comparisons?

Is it safe to use the model from the 3th person controller as a refference for scaling the world and models? I´m using a model that´s supposed to be 30cms tall, the levels must be "real world" scale. I know that UNITY has it´s own scale thingy and uses it for gravity and physics, so I don´t want to screw things for using playable models too little on a big scenario. also; what I do is import the geometry of the models made on MAYA into UNITY, compare to the 3th person model, and adjust the scale, ON MAYA. I know it´s unsafe to scale rigged models inside UNITY.