if the smallest breakers are 20amp, then it is fairly safe to assume you have 12guage wire. This would be assuming the house is realitively new, last 20 years or so,
and no one has messed with the panel. A 200amp service is great and makes me think its a newer home. You can probably run 2x 1000watt lights on one 20 amp circuit
without it tripping, but that would be pushing that breaker to its max. So if anything else was running, you might have nuicense tripping issues. The wire itself can handle
the two lights no problem. If it newer wire, like last 20-30 years, the type of insulation will be THHN at 90 degrees C and that can handle 30amps.
Check the ballasts out because they have an actual full load amps (FLA) rating on them. Its possible they draw less than the calculated 8.3amp i come up with as im am using
a simple formula that calculates off of True power, however to get a true rating, you have to consider apparent power and reactive power together to come up with a real
world number.
The number to consider is 80% of 20amps and that number is 16amps. That is the ball park number your breaker will trip at. Is it exact? not likely, it might fudge one way or the
other. Add up the ampacity values of everything you have running off that circuit, lights, timers, fans, whatever, and as long as you are under 16amps, you should be ok. Every
piece of electrical equipment will have an ampacity rating on it, that comes hand in hand with getting a UL label.
Im getting used to this forum and how it notifies you of new posts and what not. I'll answer any questions best i can, feel free to shoot me more. Good Luck!