Maximum distance with DL2

Does anyone have any advise on the use of a DL2 to shoot a image on a building 180' away from the Light? I have a client that wants to shoot a logo from the roof of one building to hit a flat wall on a taller building across the way. I was wondering if doubling up the image with two units would help. The building we are shooting at is under construction and dark. Any thoughts would be apreciated.