Ultimately, a 5-gallon pot is sufficient for permanently maintaining mature plants of most varieties of chile. Of course, with this size pot and plant, you won't be having too many indoors under grow lamps, but hopefully by late next spring you'll have determined some way to put them outside under real sunshine. P.S. Watch out for aphids, mites, and other pests on indoor chile plants. Brent Thompson Growing chiles under lights works well, but you have to remember a few things. So, you need a combination of the two types of light to get best results.
Sunlight has the full spectrum of colors.
A cheaper alternative is to combine fluorescents and incandescent's. Beware of growing in a cool, moist environment, or you will get bland fruit. Dryness and heat give the best hot flavor. The most recent issue of Organic Gardening has a really well written article about grow lights. It includes a sample spectrum for the different light types, info on what plants like, and a cost analysis comparison of some of the higher energy grow lights.