The narrow aisles in the 'straight' version of the layout bothered me, so I imposed a slight 'tilt' to the tables with respect to the walls. This turned the two narrow aisles into much wider spaces, entered through 20 inch wide 'choke points'. Had the greenhouse been a full 12 feet wide, those choke points would have been just shy of two feet. 'Tilting' the layout allows for the addition of an 'outer loop' around the edge of the room, though in most places the shelves for this would be less than 16 inches wide and not even half that at the choke points.