Ace of diamond or black diamond is what we use. save yourself labor, rent a brown bed trencher. We charge $4-5 per linear ft. Straight lines are staked at minimum of every 4', curves sometimes as close as 1'. Make sure the ball is about 1/2 buried under the grassline. when connecting them, cut the top off (ball) off about 3" then overlap into the new edge and stake the connecting pieces.
I'm very anal about edging, seen far to many hack jobs and edged that heave out after the first winter.