In Substance designer, one of the most important parameters is the tessellation. the scale and the subdivision level will enable you to visualise the modelling you are making in your Height map. don’t forget to vary the elevation of your elements in relation to each other. Your column has to be interesting visually from every angle, so the work on the silhouette is of great importance and will impact greatly on your final render. try to interpret your texture as a volume and not as a 2d map to take advantage of tessellation.
When you’re making your bas-relief, these details are going to help structure your column and will be the main elements for catching the viewer’s attention. Keep in mind that your composition also has to be clear from a distance and not only seen in close up, so spend as much time as necessary to find a good balance between details and readability.