Doing 2 more of the 460nm blue is going to push it past that 15k look you're going for. If you want to maintain the same look I would suggest another Ocean Blue and 460nm Blue, or if that gets too white for you then do a True Actinic and 460nm Blue. Or if you just don't mind it being a bit more blue just do the 2 x 460nm Blue like you mentioned. Personally, that's what I would do.