I’m going to give that version a try. My hair is a bit on the too dry side after using the too much SCI recipe.I couldn't find C14-16 either. I bought some from Alioop who was destashing her inventory. I used SLSa as a sub in the More Mango recipe, and pH was in the 5 range. It's become my favorite shampoo bar. Compared it to the bar that I made with the C14-16, and I didn't notice a difference between the two.
As for the DIY recipe, their formula uses SCI at an unsafe rate. The creators' reasoning for the high usage is not sound, per two chemist friends (one of which is a cosmetic formulator). The water during use does not negate the safe usage rate of the shampoo bar. Even in concentrated forms, products need to follow safe usage rates.
Once again and not enough: thank you one and all for advice and support!