I agree with both of those points. The 45 min is fair, even if it means Eustache's The Mother and the Whore doesn't count, at least it permits Paris Belongs to Us, which is less debatably Rivette's first feature.swo17 wrote: ↑Sat Jun 12, 2021 1:53 pm45 minutes could be a good practical cutoff point because that's how IMDb tags shorts, making it much easier to skim through a director's filmography and identify the first feature. (Note though that some films for which the runtime has not been identified will obviously not be tagged this way.)
Then there's also the question of how to pit impressive debuts from cherished directors against films that are the best (or perhaps only noteworthy) thing that director did. For instance, Hard Eight is awesome but also the most generic film PTA has made. Personally, I think I'd tend to favor more of the one-offs
As for how to decide a list-contender, I'm going to follow a similar logic if not completely. Hard Eight won't make my list, but other films that are nowhere near my favorites from the director will. Breathless is a good example- a film that may or may not crack a top ten Godard list for me, but is so revolutionary and screams a passionate immediacy by the auteur in question that it'll be hard to think of a film better suited to top my list.