23" should be enough. For casing, it's just the size right? Is there anything I should take note in choosing a casing?
Well there is a lot things u have to look.
1) size of your mobo (matx cant fit in itx case, unless they specific.)
2) number of fans u want to install.
3) want a silence casing have to find those have fans holes. been cover up.
4) suitable to put either a triple fan, or double fans radiator.
5) number of usb ports u want, like 1x 2.0 and 1 x 3.0/2x 3.0/2x 2.0 and 2x 3.0
6) enough head rooms for your long gpu cards.
7) want a side panel window or cover up.
8) enough space for cable management at the back
9) Air CPU cooler height clearances.
PS: everything is not base on ranking or what-so-ever , its just want i think when choosing a case.