again, politely, this is not the right forum, you want "indoor growing" or people will continue to hassle you to no end. in fact you can probably go there and search for gavita and answer every question you have 6 x over. double ended tech has been around for a good 5 years now and there are other manufacturers as well. i would never buy a gavita as they are poorly suited for most applications other than high-ceiling warehouse. if you really want a nice double ended system get an sun systems acde hood and an ushio or hortilux bulb with a solistek matrix ballast. in the end it will cost you more than LEDs with bulb changes ad electricity bills, but if you want quick return its hard to beat that setup for $600
growershouse is a good resource for you. theyve got shootouts of every major component of an HID systems:
http://growershouse.com/blog/hpsmh/
last post about it from me here in the LED forum, but that should get you going in the right direction