That shows overall diameter and baffle hole diameter, which can be used to determine the width of the routed groove. Depth, on the other hand, isn't listed there. But the depth should be to 5/8" to 3/4" to make the driver appear flush.
The rubber surround actually protrudes past the front gasket, even when the driver is at rest. So to make the gasket flush, you would want a 5/8" depth recess. The get the surround to be flush, you'd need a little more depth, about 3/4".