You can use a label instead of a level dim. The trouble with using a label is that the slab has to show in order for the label to show, and the label will show on any story the slab shows on.
Two of the most frustrating half-done features in AC are labels and RCP production, and here we struggle with both.
Here is my slab label from a while ago. In the comment script I credit Geoff Briggs for help, so I'll mention it here too.
