I suppose "best" is always in the eye of the beholder - and what's available. As editor it's your call to make.when you have 3 similar versions of the same poem, how do you pick the best one?
In the comments of the article someone who claims to have worked for Black Sparrow in the 70s said, "when we received Bukowski’s mss. in the 70s, John wouldn’t let anyone do more than correct the spelling," so I suppose those 70s and 80s Black Sparrow versions are very close to Bukowski's intentions. But then there are examples of changes during that time that do not seem to be in line with those intentions, so we know Black Sparrow sometimes did more than correct spelling.
But "better" is always going to be subjective. What is "strong" or worthwhile is subjective. Whether "tighter" is better is subjective. It's art, after all, so everyone is going to have a different opinion on every piece. There are plenty of people in the world who believe that Bukowski never wrote a single poem that was strong or worthwhile. Imagine if you had to deal with them and their opinions. ;)
I wouldn't want your job, but it might be a good thing that your audience is nit-picking. It means they care about what you're doing. That what you're doing is important to them. And that's much better than silence and apathy. Look, we're all alive here together! What could be better?
I appreciate what you're doing, for what it's worth.