you dont have much rock to pull out. in my opinion, pulling out sand as appose to rock will add to the minimalist look youre going for. BB is not for everyones taste but my opinion is BB with minimal rock work is such a clean, modern, sophisticated, and minimalist look!
edit: looking at ur beautiful tank and had one last thought: if u were going to make adjustments to ur rock work u may want to consider a little asymmetry! both islands look similar is size, perhaps making one island noticeably bigger then the other and/or even adding a third really small island....