Just to re-iterate what has been said:
-"Miltaries" are done to the front, unless 'behind the neck' is specified.
-Bring it down to the collarbones, similar to a front pulldown.
-To keep tension on the delts, I'd go just short of lockout.
Also, just be wary of seated presses. Sometimes, it's tempting to turn them into accidental incline presses. So, count that as a vote for standing, instead of sitting. Plus, when standing, you can throw in some push presses or jerks to get out an extra rep or 3 to extend the set, as well as handle slightly heavier weights.