I read this when it was posted, along with the Guest Post. What just occurred to me is that it is not the weight (mass) of the wet clothes, but the weight (mass) of water to be removed that should be considered. I will argue that the data collected cannot be used to answer the question posed.

You probably also need to calibrate the dampness sensor to be certain it signals 'Dry' consistently, and at the same level of dryness for differing materials and environmental (background) conditions.