KNNA, Thanks for the info. I was able to comprehend about 80% of it.
This will give me an opportunity to educate myself trying to understand the other 20%.

Another question: I bought some LED drivers, 24 volt, 180 watt, voltage regulated.
Why are the larger wattage LED drivers all voltage regulated? instead of current regulated like the small drivers?
Is the voltage regulation tight enough that you don't have to worry about excessive current swings. Or is it expected that you use secondary current regulation, like a resistor or a reg chip in each string?

I am currently using a resistor in each string since it is cheap and simple. I could make some small reg circuits if need be, but am lazy. I burn them in for a couple hundred hours, then I customize the resistance on each string to get desired current.