I am not writing from a place of extensive experience, but I have made my recipe a few times and been happy with the result.
I use 1 teaspoon in 1000g of soap. I tried to use more, but the extra salt and the sodium hydroxide cant be held in solution in my water volume.
I tried increasing the water volume to allow for 2 teaspoons of salt but wasnt happy with the soap consistency.
So I am back to 1 teaspoon, and it does certainly help with hardening up the soap to unmould.
my basic 1000g formula has
olive oil
tallow
coconut
castor oil.
1 teaspoon sea salt
2 level teaspoons honey
and 3.65g sodium lactate
Thank you for your help. I'll add it to my notes!