First it sounds dangerous. However the mulching blades I've seen have a stiff spring mounted to the blade such that when in motion it drags the ground. The spring has a tip of straight about a few inches that touches the ground. The coil portion does not. Also the straight tip is what drags the ground and it tilted in the same direction of rotation. This way it gives and just rips the top of the ground.
I will say after using one of these on a lawn mower. They make a lot of dust. I mean a lot.
Mounting bolts that point downward from the blades I think will break a shaft when it hits something solid like a root, rock, etc.
Anyways, Mounting parts to the blade sounds really dangerous as the ends are moving really fast. Making that much contact with the ground you are going to break something and will be dangerous when it goes flying.
I think rippers may be the cheaper alternative.
