The 4-blade prop should work very well in the rough water conditions and will generally get the vessel on plane faster. Although it is very important that you select a prop which will allow the motor to run in the recommended RPM range. The stainless steel prop will normally range one size pitch higher than an aluminum prop. Your best bet would be to locate a dealer which will allow you to test various props to determine which one is absolutely the best for your rig.
You can read more about choosing the right prop for your boat’s motor in my article Choosing the Right Prop.