well i'm noticing three things; first your plants need the spectrum that the2700's are able to produce, so if you add 6500's the only thing it will help is by adding lumens. these however are not the right specrum so your plant will not really respond to them. your better off giving it more of what it wants. they are females you know.
second whats up with the splitting, doing this will cause low initial amps. thus ruining your lights future potential. buy a surge protector for 30 dollars. i run up to 10 lights off just 1 or 2 protectors.
last your plants look great from what i can see so if you add more lumens now your plant will grow faster causing imballences (more production in different parts of the plant) in the stalk and the buds will be loose from the stalk and not as dense. not trying to bum you out cause it looks like a set up she likes.