Hi Davide,

I think the common opinion now is that 24" would be best for you. So there are only a few advices left: use the chance to experience the views in your mates 24" if it fits your needs! And last but not least: consider the seeing at the places you plan to use. Is the power you would use possible in most of the time at this site? Is it possible to magnify > 600 in rare nights or quite often? At least for me fine stars are more important than bigger smudges...

CS
Norman