I've also re-read Tonya McKay's article, which mentions that specific polyquat. For those interested: Low-Shampoo or Co-Wash Routines and Polyquats
F - LP - HD - NE
Fine, low porosity, high density, normal elasticity
Hairtype 2c

Low poo: Weleda Oat Replenishing Shampoo
Protein: IAGirl's gelatine treatment
Detangler & LI: KCKT
Styling: KCCC

Beauty Is Not a Number