I have read both de Courday and volumes 1 and 2 of de scheel. Within the discussion of canister and how it operates it is relevant, but the equipment and canister was modified by Rostaign and Manson in 1789-1791. De scheel and de coudray are writing about superceded equipment.
Both are really good for the politics and arguments on either side about the adoption of Gribeauval.
In my comments on canister I was pointing out we dont know exactly how canister works to get the balls from the canister. I presented data comparing the effectivness of Gribeauval and System AnXi canister types as well as a description of the construction of both.