My son swears by straight shea butter on his heels when they become dry and cracked. Maybe some infused calendula in a light healing oil mixed with shea would be great, too.
As Eugenia stated, stearic acid is not needed in your soap formula at all. Some soapers use it to firm up their bars a bit. I experimented with it in my beginning days of soaping. I have used up to 5%...beware, the soap mixture will move very fast!
You could try: coconut 25% lard 15% mango 10% olive 40% avocado 10% or grapeseed or macadamia oil etc. Or you can even do away with the mango ( save for a lotion or cream ) and just use 25% lard. Happy soaping!
I've never had trouble with getting a castile soap to come to trace. The longest stir has been approx. 15 min. As far as curing your precious castile, give it at least 6 weeks. The longer the cure on a castile, the better it is. :smiley2: