I know I'm considered "old fashioned" and a minority of one on SMF, but this is based on my experience over the past 13 years and it may help someone.
IME thin liquid soap is just the nature of the beast. Once you understand that and focus on the lather created, that beast turns into a beauty. A good example is 100% olive oil LS.
The amount of dilution water needed depends on the oils used. For example:
100% coconut oil LS dilutes best at 40% soap to 60% dilution water.
100% olive oil LS dilutes best at 15% soap to 85% water. Thin, to be sure, but wonderful lather! It can then be thickened with salt brine. A better option is to add castor and/or coconut for a better viscosity to the finished LS. (BTW, this also works for 100% almond oil.)
All other oil/fat combos fall somewhere in between, altho 50% coconut oil to 50% liquid oil does dilute quite nicely at 35-40% soap to 65-60% dilution water. The end result generally has the viscosity of commercial shampoo.
So, unless and until you try it, you will be amazed at how much lather you get from a 15:85 ratio for 100% olive oil. You may prefer a molasses type consistency, and that's fine if that's your preference. No worries. BUT your thick OO LS takes far longer to rinse off and a lot of soap is wasted down the drain.
Another thing to keep in mind is that you will know the LS is at the perfect dilution rate when a skin forms on the top. Add a bit more water to dissolve it back into the batch and you're done.
Because there isn't enough head room in a crockpot, I dilute the paste range top in a large SS pot. I chunk up the paste, add it to boiling water, turn it down to med/low or low, put the lid on and let it do its thing over 3-4 hours, stirring gently every once in a while to break up large pieces. The idea is not to cook the soap, but rather to get the water to absorb the soap over time. Dilution happens "all of a sudden" when the soap reaches 160°F. (The water may be hotter than that, but it takes time for the soap to reach that temp.)
ETA: I also use only water, no glycerin, to make the lye solution for most of my batches. Just my personal preference based on my experience. The exception is when I make LS high in olive oil or other liquid oils. Then I use
Carrie's GLS method, subbing glycerin for all the water in the lye solution. Using 16 oz. oil, this turns into soap in all of 2 minutes using a stick blender -- just like it shows in the video. It does indeed test clear with a drop of pheno solution after a one-hour rest. Way better than the first time I made OO LS -- it cooked 10 hours (!) before the paste tested clear.
View attachment 30151 Hope this helps someone.