That shaving soap thread is a great read. The amounts I settled on in the end were as follows...
Stearic 45%, CO76 25%, Beef Tallow 20%, Lanolin 5%, Shea 5% all at 5% SF (reserving the Lanolin and Shea for the SF). 100% KOH at 33% in water. Essentials Oils 3% (Lavender, Rosemary, Mint)...