Blue and red spec mix?

Ok, I know alot of yall mix the blue spec cfl's and the red spec cfl's together usually in a 2 to 1 ratio for either veg or flower, but is it better off to go straight blue for veg and red for flower, or blue for veg/mix for flower, or the final 2 to 1 mix for both?

Wondering if anyone has actually got some data on this..

+ rep for any good info and help!

-pc