And in the narration of Al-Kahili and Husayn bin Al-Mukhtar, from Abu Abdullah عليه السلام:
Imam عليه السلام said: "The recommended amount for that (camphor) is four mithqals."
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 1, p. 308