cob dim dimming

I have a bar of 5 Cree CXB3590's running at max 250 watts, that I have just moved over the top of my seedlings. They are only about 2 weeks old so just little gals. I have the LED turned all the way down and up about 21 inches above them. When can I start cranking up the volume??

Any thoughts my brothers what gives me highest yield results, im looking for weight!....

So I think soon I should be able to pull the trigger on finishing my upgrade to COB's. My idea is to use 5 bars each using 5 cobs spaced approx 12" on center on each bar then have each bar approx 12 inch away from the other bars effectively getting 1 cob per sqft. in a 5 x 5 space. My first bar...

Just interested in how people are using the dimming functions (if they are) on their COBs. There are a lot of HOW to dim threads... but this deals with WHY and WHEN to dim. And do you want control to dim outside so you can dim before you even enter the room/tent?