Gezz still no replies!
Id like to know aswell, but i guess if you have anything that flowers/fruits late winter could be done under 12/12, and 18/6 for veg. You could probably get away with lettuces under 1212 if your temps arent too high (high temps and slow growth equals bitter taste), and the obvious dope companions are tomatoes, chillies and peppers. Opium poppies are common too, they grow under 12/12 light and flower under 18/16, opium is pretty useful to have in the house as a natural painkiller, and goes well on a joint, just remember its fucking addictive.
hope Ive earned some rep haha,
Someone like ANC might know more, Id be interested in more in depth stuff, and i guess it depends on ones setup too