One additional downside of running a single strips. If you plan on disinfecting a rack (I would suggest that is a good idea) all the 'safe' disinfectants require saturation for at least 10 min that means wet quite wet. Power and liquids do not go well together. Independent strips allows one shelf to be done at a time and not needing to remove the heat from the whole rack at once. Racks save space but I have never found them faster to clean or easier to heat.