For roofs, the ideal setup would be three small lights, wired with about 6 - 8 feet of wire b etween each one. Each light in it's own little "bullet" with a diffuser dome pointing up and the base resting on the ground. 3 or 4 of these in a "snake" could be laid on the ground under the roof, each one illuminating part of the path. I feel this would be better than 3 lights under 1 dome, which is essentially a lantern without the light limitation of a cap.
And of course, props to you elblat... for doing something weird and awesome in your spare time.