Sir I would like to do an neem oil sopa sir ,so to get a good lather and cleansing properti for dry skin can you suggest the oils with the ratio? Neem oil Palm oil Coconut Castro

How to preserve hot process liquid soap ?by both chemical and natural way. )if chemical means how much grm I need to take for *100grm of shampoo base + Required quantity of water to dilute*? Types of preservative,and their quantity . ) if natural preservatives means their quantity used for *100grm of shampoo base + Required quantity of water to dilute*. Types of natural preservative and their quantity. Pls sir