In addition to making fixed, false walls that would be set directly over the mail boxes I decided that I could build something movable that could leveled with a screw-jack so that the wheels would become inoperable.
In this situation there are pilasters that are 1'8" wide. The design would adapt to this with metal framing and there would be strategically applied plywood strips where nails or screws could be set for paintings to hang upon.
Even with higher wattage incandescent flood or spot lights the total wattage could be handled by just two more fifteen amp circuits. With the new LEDs - though more expensive to purchase at the outset - would only require one circuit.