While it is certainly possible to use a roster, I don't like having to refer to another piece of paper during the game. Call me lazy.
My system uses 1/2 x 1 1/2 inch steel stands glued to the back of the command stand. Rating labels are then stuck to adhesive magnetic sheets. By simple changing out the label, the unit now has its rating visible on it on the table.
My original labels are shown below:
Functional, but hardly inspiring!
I've been playing around with the label style, and eventually settled on labels that reflected the unit's uniform - tunic color on top, trouser color on the bottom, facing or piping on the left. Rating on the top and unit name on the bottom. Examples of the Confederate system in practice are shown below:
I think the new style is a lot more visually attractive, and conveys more information than the old, generic style. So far, I've created Federal/Confederate and French/Prussian FPW labels. Its not a fast process, but the end results justify the expense and effort.