What about something like Sunday August 9 at 19:30GMT (right between any other reoccuring events)? That's 3:30pm EDT, 12:30pm PDT, or 8:30 in GMT+1 (I don't know any fun initials for that). I guess that would end up being like 7:30 in Australia?
Ok, ship-wise, how about each needs at least 1 Transport, then a 3:1 Fighter:Bomber ratio? Possibly only the Dragons/KNF fielding them?
On the one hand, NT makes sense for an ambush, but it's also more readily able to provide reinforcements. I'm thinking as soon as the Samura's side gets through, the Dragons and company block the gate, preventing anyone incoming or outgoing.