All Starting Structures Previewed in Editor

Please add an overlay for all of the starting things - Settlement, radio tower, workers and dock, into the editor. At the moment, there is only the dock, and its model is smaller than what spawns when the game starts. I am trying to measure the spawn area before constructing my map, but despite there being no errors, the map won't load because of a 'Failed to build Radio Tower' error. Rather than guess where everything will appear, I would like to see them before publishing.

Attached is a screenshot of the smallest flat area, 5x5, and the error when placing a plateau. Does the tower require the same ground height as the shipyard?