IIRC it looked like a tanker with a three sided structure on either end and Sprint like silos in-between. something like an early Arsenal Ship.
Well, each level of technology dictate its own decisions, do not you ...?
As for the helicopter: actually I thought that the helicopter at the usual time hide in the hangar, integrated into superstructure. The screw is composed, the tail bends to the side.
That is based on the fact that a situation where the ship will have to SIMULTANEOUSLY keep the helicopter on the deck and shoot anti-aircraft missiles are rare.
However, I personally think is an anti-submarine drone to replace the helicopter.
Attachment:
Sirius-class.png
Thus, some modified version:
1) Removed the torpedo-tube
2) Added additional antenna control anti-ship missiles on the mast
3) Improved helicopter hangar door in the rear of the superstructure