Nope, just the closest point of the target ship needs to be in arc, and at ranged 2 at the time of the attack. That's all it it takes to trigger the effect.
But this concept of closest point being in arc has no support from the rules. The only place it exists is a single email from a FFG employee.
Implicitly, tactician uses the conditions of the attack to determine if the tactician effect triggers.
But nothing about the turret rules suggests that "in arc" is determined by anything other than some part of the target ship's base being between the arc lines. There is no rule that "in arc" is determined by a line from the closest point.
While I understand that it's not exactly what the card says, it is evidently, exactly what the card means.
I don't buy this argument at all. The card means what the words say. Until FFG makes an official ruling otherwise (and no, an email from a FFG employee isn't official) I don't see any reason to assume that the intent is to do something that directly contradicts the normal rules.