Suzip. That was a part of the article I especially liked, because it does - to some extent - vindicate OW's stance on the portrayal of the character, Montag.
In the actual diaries, Truffaut keeps writing about how the movie was "Science Fiction" and because of this, it could not hold by the "traditional" cinematic tropes -- i.e, romance, seduction, etc. So, it seems as though Truffaut was trying to out-Science-Fiction Bradbury's characterization of Clarisse. I'm beginning to think it had more to do with Truffaut's own insecurities of tackling a "Sci Fi" film (something he had never done and would never do again) then it had to do with anything else. I also believe that OW knew which side his film-career bread was buttered on -- as a matinee idol. It seems only natural that he would want to build on it in this film as with all the others up to then (and which he returned to with great success in "Interlude").
But, essentially, the gist I get of the Truffaut/OW conflict during filming was what would happen with two brothers squabbling (with OW being the "older" and Truffaut the "younger").