For one chameleon, only one. Or you can do two: one with a higher wattage bulb and one with a lower wattage bulb. example 75watt and 50 watt.
Do a 'spiral' with a vine underneath the basking spot, or have 3 levels of perches so he can regulate his temperature.
If he's an adult, 95F at the maximum, then 90f, then 85f. Those are good basking spots.
If it's a girl, 92F as a maximum IMO, though some people like to keep their females in the mid to low 80s.
If it's a baby, you want about 82-84F as the hottest spot.