Yeah, so i already have these drivers, and i want to purchase some quality cree LED’s to use with them… the only thing is, the drivers output 600ma, whereas, all the 3w cree LED’s are rated for 1000ma…
will i be able to get decent lumens using 600ma driver, or maybe someone knows of some 600ma 3w cree leds i could go for?
cheers.
They will be less bright but will run forever, you will also get more battery runtime.
Leds rated for 1000mA should not be run at a higher current (although we tend to think different about that, over here 
), but can just be run at any lower current up to 1000mA, so 600mA is fine, and plenty bright for most occasions.
Take that back, there is no such thing as bright enough. 
Yes, sorry that I said that, don't know what got into me 
It reminds me of Langcjl's sigline 
: Piers said " ....but who wants enough light, when you have the option for far too much "