I am going to help my 5 year old niece make some M&P soap for her parents for Christmas. I have enough samples of several types of M&P base. I have been doing some reading on CT board and have a few questions. 1. Something I'm not sure about. Does castor oil make the bar harder? If so, how much should be added to a pound of soap base. 2. I also read where you put goats milk powder in the base after you have mixed it with water. Is this tap water or distilled water? 3. What is the total amount of all extras combined that should be added per pound of base? Whatever I add to the base has to be found local since I don't have time to order. I know, last minute but my niece just asked if we could make this for her parents. Thank you.