The 'square' concept keeps coming back periodically because the rags have pages to fill up.
There's an interesting discussion online from 2007 'at another shotgun related site' as it were, easily found with a search, between Wakeman and Lopez. It sums up the debate for those interested.
Personally, I find the biggest variable as far as performance to be shot hardness. An extreme example was trying hit anything with Rio 410 shells. That is as dismal a factory load as can be found. Sure enough, they contain (or did at the time, about 8 years ago) what can only be drop shot.
If there really is a 'gauge' that performs better than it has any right, it's not the 16 or 28.... it's the 410 (with good shells), and that's about as 'over-square' as can be.
