Jackson's are a bit more difficult to raise from babies in captivity for some reason. It is very rare to see true captive bred Jackson's adults for sale. By saying the seller is a breeder, I'm assuming he's at the very least led you to believe this is a captive bred animal? I'll be the first to admit anything's possible, but I suspect unless you're paying more than $150 for him, what you're getting is most likely a WC jacksonii xanth from Hawai'i. Nothing wrong with that, they can be quite hardy once they're past the 5 or 6 month mark. Just letting you know.
They will really do best when kept outside as much as possible. In the wild they take temperatures down to almost freezing on a lot of nights. There are reports of the sympatric Von Hoehnel's chameleon active and walking around on snow covered branches! I only bring mine inside when the temps get down to the low 40's, and sometimes not even until the upper 30's. Mine are more than happy to eat and be active on days that only get up to 65F. During the summer, we had some days that got up to 85F here. At the hottest time of day I would go outside and find my Jackson's almost black and lateral basking at the end of an exposed branch. They do love the heat and basking too. Being in Arizona, when it gets above 90F outside, I'd make sure there's plenty of shade, a breeze, and if possible almost constant misting to keep him cool. This would be very different from your veileds which could take the high temps without ill effect.
As far as lighting and supplement goes, i use reptisun 5.0 for all of my chameleons as well as miner-all and Rep-cal.
