We are doing a retaining wall project where we are extending the existing driveway. The home owner wants to do asphalt for now (hopefully pavers down the line) so we are just going to install the base for the driveway behind our retaining wall. Generally we backfill retaining wall with 3/4" clean stone. Would we do the same in this situation? and how many inches below the existing driveway should we leave the final height? the first picture is the back end we are extending- its about 14x16 and the second picture is the left side- thats about 3-4' wider than the existing driveway.