If you are breaking props, you are either taking off or landing wrong or you are trying to fly off of a surface that your plane simply can't handle. A broken prop is essentially a crash. You wouldn't build your plane heavier and stronger to help it survive nose in to the concrete crashes, so don't try to buy more durable props to help them survive misuse.

If you broke a prop on your takeoff roll because the grass was too tall, then you are trying to fly in way too rough an area. It will never work. Look for a smooth surface to take off on, preferably something paved but well maintained park grass will work with wheels on the big side.

And I'll second what others have said- don't try to re-engineer the Apprentice. It's darn near perfect out of the box, so adjust what you are doing to work with it.