It sounds like 5 blades are worth a try. They should help with getting on plane and also reducing slip. BBlades has a swap program that offers great value. He should also be able to get you close to your target RPM at WOT on the first try. If you can get on plane, the X isn't too high. I would work on other aspects and only drop the X as a last resort....it will scrub speed.
Welcome to HP power boating, it is never perfect!