There's also drying alcohol as the second ingredient in that activator, that is worse than the silicone IMO. You can add magnesium sulphate (epsom salts) to flaxseed gel for more of a curl boost, but that can be drying so don't overuse it. I would make you recipe super simple initially, if you add multiple ingredients you won't know which works and which does not.
Magnesium Sulfate: Curly Friend or Foe?
Proteins: Why You Should Care