you seem to be on the right track, what the heck to you need us for?
well again there are tons of people on here that love to help other enthusiasts out but seems like u did ur research . . . i dont think the colour of paint matter but im sure the darker the colour the more heat it will hold especially if your using heat lamps . . . but be careful with the heat lamps becuase they will take alot of the humidity away from the enclosure . . . the under tank heater with a thermostat should be perfect by itself, ball pythons require belly heat and spend most their time in burrows underground during the day and come out at night to hunt for food so they dont tend to need too much lighting either