What I would do is scale up over a period of time. Obviously, there is a point where you cannot go any farther, because of heat problems, or electricity usage or whatever. Estimate where that point is as pertains to the number of lights, cut that number in half, and try that to start. If you think you can handle 4 1k lights, try 2 to start with and see how it goes, then reassess. If all looks good, add a third 1k light and continue, and so on. That way you shouldn't have too much wasted expense, and when you do pass the point where you start to experience problems, you will know exactly what you need to remove (whatever you just added), to eliminate the problems.