The mirror is definitely not ideal. Flat white paint is the easiest/cheapest and very reflective. Mylar is the best, but cost you more. Mirrors are poor reflectors of light and have potential to burn your plants (hot spots). I'd say lights on for 24 hours while vegging. If you were using a MH HID light, then I'd say cut it back to 18/6. Any other light, and they need as many light hours as possible.