If it has a divider, put that up….otherwise oh well lol. The way I look at a 4x4 space is in 4, 2x2 quadrants. One plant per quad with a cob above it. That should do great with proper light distance, with reflectors. In my experience, 4 cobs with reflectors, or 5 without per 4x4. The extra lights I add are a different spectrum for flower, and are less strong…. I ran for years with one cob per plant. Had some great yields over that time….strain selection and pot size will be the things to consider…..