I know Blackhawk Carbonwood Vapor's,the 3000 spine at .400,the 4000 spine at .350 and the 5000 spine at .300.If you are wanting to get around 650 grs. I would go with Carbonwood 5000,the Carbonwoods are heavier then the black Vapors to start with and the spine should be stiff enough to add front weight and still get them tuned.I shoot Carbonwood 3000 out of a couple of bows,the 3000 is 30.5" BOP,100 gr. insert and 125 gr. point with wraps&3-5.25 feathers give me a total weight of 530 grs..Is your bow cut to center?5000's may be your best choice to get 650 grs.