Over-the-Air vs iTunes update - which one are you doing?

[Killerbob]

I live in Greenland where we have metered download. Hence it is relatively important to me to optimise the upgrade... I have 3 x iPhone 5S, 1 x iPad Mini (1st gen.) and 1 x iPad Mini (2nd gen.). I also have an iPad (4th gen.)

Can I download one update file from somewhere, or do I have to basically run update 5 times (via iTunes), or should I go via OTA? I really have a challenge if we are talking 25GBs of download...

Thanks in advance for suggestions...

 

[makefunnyfaces]

iTunes because I'm home. Would have done OTA if I were out.