1. In Game-Piece Image Definitions, create a layout for all the "images" that will be named "1" through "18" and "0.5 (1)" through "12 (18)" - completely clear (blank) borderless images with only a name and nothing else.
2. Create a Dynamic Property that is numeric, with a minimum value of 1 and maximum equal to the number of levels in your game-piece layer. In the example from step one this would entail 36 levels: 1 to 18 plus 0.5 (1) to 12 (18).
3. Create a Game-Piece Layer with multiple levels. Each level should use one of the images you defined in step 1. Note: If you create levels without images and merely give each level a name, the level names will substitute for $pieceName$ in the map's auto report fields.
Set the layer to "follow an expression" where the expression is simply the name of the dynamic property.
Example: see Hood Strikes North module of the GCACW series.
In this instance, configure "Combat Value (Manpower Value)" strings to follow a Dynamic Property called "strman" so they are displayed in the mouseover stack view under each unit.
In the Map component called Mouse-over Stack Viewer setting "text below each piece" enter:
This will display the image name used in the current level of the game-piece layer named <layername>
No image will be shown on the game-piece, since these are all clear images.
Confusing because each layer has a name as well as each level within a layer.