What download options do I have for an album? I want to control this per event.

Four modes, and you set them per album so different events can run differently. You can let guests download full-resolution photos for free — the default most photographers use. You can charge per photo. You can charge once and let the guest download any or all photos in the album. Or you can disable downloads entirely and let people just view. The per-album control is nice because a corporate event might warrant free downloads while a destination wedding becomes a revenue stream.