Truthfully, I think we'll be able to make the call by the next international break. Realistically, I do think we're plodding on until November/December.
We really should be good enough to get to the Arsenal game at the start of December relatively unscathed. We're obviously not going to win every game, but the toughest games between now and then are Spurs at home, Villa away and Chelsea at home, with Porto and Fenerbache away in the Europa. Even then, I'd argue every game falls into the "eminently winnable" category in isolation, with us being clear favourites in the majority, regardless of where we're playing.
The problem I have with "top 4 minimum" is that City and Arsenal are simply better than us, and it'd take a massive drop off from them as well as a massive improvement from us to overtake them. Liverpool are also better than us, but there remains a glimmer of hope (even after last weekend) that Slot can't keep them going.
We're looking at competing for one, maybe two spots, among a group of five or so clubs who are all of a similar quality to us. As I pointed out to DSG, who marked 75 points as the "safe" total to achieve top four - we've only managed that twice in the post-Fergie era, and that exact points total wasn't actually enough for Arsenal to get top four in 2016/17.
I think the league is simply too competitive now for us to be making such a bold expectation our "minimum". You basically need to reach the midway point of the season with at least some degree of hope you could win the title to have a comfortable top four finish these days, and if you're not good enough to do that (even with the acknowledgement that it'll likely tail off as the season comes to a close), you can't expect fourth as a minimum. We simply aren't that good.