Thanks So much that's good news I've been only using consentration and my soap usually turn out pretty good.Water-lye ratio and lye concentration are the same thing, expressed two different ways. I use lye concentration bc it is one number with no colon, so it is easier for me to see and read and write it down accurately.
Either of those settings will give you good consistent results no matter what batch size you use. You don’t have to fuss around with “water discounts” - simply raise or lower the lye concentration or water:lye ratio.
Water as percent of oils can give you inconsistent results when you change batch sizes. It usually results in waaay too much water for my liking, which in turn, creates a lot of soda ash and glycerine rivers. If you want to reduce water with this setting, you must do your own math outside of the soap calculator. As someone who seems to be dyslexic with numbers (but not letters), the less math I have to do, the better everything will turn out.
Bottom line, I recommend using the setting that works best for you, and sticking with it so it becomes second nature and one less thing to fuss about while you are soaping.