Here are some photos of the wip ballturrets.
Cannon assembly: These are the side "disks" that pitch up and down on the sides of the ball turrets. They have the cannons attached.
This is a (temp) assembled ballturret in its socket: The center section of the ball yaws left and right. The hatch with its viewport is magnetically attached, it can be lifted off so you will be able to see the gunner inside.
An overhead shot of the hull + ballturrets: Thompson & Thomson can be seen off to the left, they are getting their paint job prior to being installed in the ballturrets.