In some cases 100 percent may be visible. They will be on the upper side of the drums, but the drums may be on their side or at an angle. In any case, the label will be on the most vertically visible portion of the drum. The Figure indicates examples of drum orientation only. Not unless you want to do this as well.
Drum centroids are all that is required.
The disks will be painted Day-Glo orange. Spray-On distributes the aerosol concentrate under various labels. In the United States outlets such as Home Depot, NAPA, and Target stores sell paints using the Day-Glo fluorescent pigments. Home Depot building supply stores are one outlet for this brand. The Day-Glo orange paint is applied as two coats over two coats of white primer.