I used the full amount of glycerin in the video PLUS 3.9 oz H2O. Sorry, I should have been more specific.
Most recently, I used the recipe for shampoo gel from thesage.com:
https://www.thesage.com/recipes/recipe-exec/.State/Display/id/114
I do not love it. I have very long, very dry, naturally curly hair that is prone to frizziness. Even though it is very liquid, I simply can't get this stuff through my hair to my scalp in anything resembling a reasonable amount of time.
I used the glycerin soap/shampoo recipe from Soaping 101 with MUCH better results.
It is much thinner, but so very much better. I won't be adding coconut milk to it again, though. I think I just prefer the straight soap with a bit of jojoba oil added with EOs to kick in some extra conditioning.
Just my experiences thus far. YMMV.