I have tried my soap tonight. It is fine to use, no Lye remains and it doesn't strip the skin from the bone or itch or cause irritation of any kind. As a first effort it's OK, useable but there is no fragrance to the soap with the 15 drops of fragrance oil I used according to the recipe. It needs a heck of a lot more, however that will make it expensive and I do not know what the oil will do to the skin properties of the soap. Essential oil can cause bother if used neat or at high concentrations. So I'm happy enough to use the soap to wash and then apply something smelly once out of the shower.
Next batch which I will make at the weekend will have coconut oil in it, this will help with lather production. The Castile soap doesn't lather a lot, it does produce a thin washy lather but it would never make a shaving soap. It does clean well though and is moisturizing, I think it does need the Coconut in there but until I make it this is just pure speculation.
It's a nice useable soap. I'm happy I gave it a go and will be making more.