When I designed my main LED light I bought 2 sets of drivers, 4 of the D models and 4 of the PWM models. This was because I knew I wasn't going to get the PWM part setup as quickly as the LED light itself and I wanted to use the LED light.. now that I am finally getting back to my PWM controller I can swap out my D drivers for P drivers. I don't think I will be selling my D drivers though.. they are still good drivers and I have more LED projects in mind where I can use the D drivers. I would like to do 2 D drivers on my sump LED light instead of 1 constant current driver so I can add more LEDs, some colored blue and red ones, to see how those do on an ATS. My design now with the LEDs on the ATS was to get a good baseline so I knew what white LEDs could do. With the D drivers I can bump up the total # of LEDs up to 12 per side, multiple colors, and dimmer control because I think 12 LEDs per side at full power on my screen would be way overkill, but I think I may need 12 LEDs overall if I go with multiple colors in order to get good coverage with the colors.