My school girl French isn't anywhere near up to reading the memoirs in the original, but I take your word for it. (The translations I've read were all 20th century ones, so basically were by necessity modern as well.)

Agreed on the immense suitability of Rupert Penry-Jones as Grimani. In the duel scene, he sells both the breakdown complete with tears and the petty vengefulness when he does shoot later, as well as the "neither of us has her but we have each other" thing.