In the beginning.... of my soaping education, I started a binder and printed out a copy of each oil at 100% of recipe on soapcalc.net to learn more about each oils properties. I'm with Shari - I combine 8% PKO flakes with 12% Coconut oil for the extra hardness properties. I use 50% Olive oil and 2% Sodium lactate, but I'll take anything I can get to find that perfect "hardness" quality.