Actually, I agree with you, or I did until I watched the film again AFTER reading Catherine Benamou's book. Before that, I felt pretty much as you did. But to clarify, in my comments I'm really talking just about the reconstruction of FOUR MEN IN A RAFT and the brief snippets of CARNIVAL footage, not about the documentary itself. I also agree that for some reason, the Ferrer narration does not work that well. Jeanne Moreau did the narration in French, and would probably have been a better choice to do it in English as well.
But have you read CB's new new book and seen the DVD recently, or is your opinion based on an older viewing of the film? One reason my opinion changed was after getting a more complete backgroud about the picture Welles was trying to make, I could now imagine what he was trying to do with FOUR MEN IN A RAFT and CARNIVAL. So the bad music and foley didn't upset me as much, just like in Welles later films.