I have made six big Fleets to the new Okinawa CT/SEA map and I have adjust them all to same port (outside the map area). It works. You must make every fleet's "master ship's" adjustments like this:
The seconf column on row "Group ID" is the Port's number, here it's 7. Put there the Port's number what you want and that's it!;)
When you are creating yoour own fleets, it's better to take the default fleet and make repairs to it. My biggest fleet in Okinawa map is 4 Carriers, 2 Cruisers and 8 Destroyers.
Don't place the ships too near each other, because the "Gun Ships or Fields" hanger picture (ships profiles from up) is then a big mess. The default fleet's distanges are good!