I grew for a long time, using only 48" fluoro tubes ... different from CFLs, they need to be kept to only about one inch above the plant ... on the tubes, the lumens fall off rapidly with distance ... your idea of a 6" hole cut into plywood, paneling, sheetmetal, etc. will work fine ... here's my roof-vent outlet, using a trick Plexiglass panel that lets me exhaust, and still get some light into the trailer (Plexi compliments of xcrispi :thumbsup ... :wtf: was gonna post up a pic of it, and I dont see the 'add attachments button' ... :wtf: