Here's an update to show you the angles at which the 4 guns on the side of each bastion can shoot:

5P17R ArtShootAngles.PNG

And here is an update on the map of the fort. The trench and the covered path are definitely smaller (36 meters and 11 meters wide) and more proportionate to the citadel:

5P17RegV1.2_250Rad_40cann_Volume_NoColor.PNG