I may be too Luddite or something on this but it seems that increments of 0.1mm in shot size is maybe too anal. The jump in US sizes from 2.2 to 2.4 is granted some significance but the 8's(2.2mm) will break targets at insane distances. Even in 24gm loads with some choke like Ian says. The 2.2mm also has enough moxie to kill pigeons so that has to say something, and it is plenty for ZZs as well. So the 2.3mm Italian things I'm guessing would be just fine.
And random samples of bags of shot for reloading, premium stuff too, shows an inconsistency that you prolly don't want to know about.Premium European shot is much better than your American stuff