Swing by a hobby shop and pick up a couple of wood props. Take a close look at the wood grain. Visualize what the blank they carved that prop out of must have looked like. Your questions will be answered a lot quicker that way.

Another reason to look at those props closely would be to compare the pitch of those successful props. It varies from hub to tip. It's worth noting what has evolved in the real world.

It's also worth testing what has evolved in the real world. It will provide you a basis of performance to compare your own design against.