16mm receding chin. Will a 10mm sliding genioplasty be enough for me? (Photo)

While a 10mm sliding genioplasty will provide some improvement it will still be very inadequate. You need the maximum forward chin movement as well as bringing it up as it comes forward. In essence you need what is known as a jumping genioplasty technique which can bring the chin forward up to 20mms....which is really what you need for a significant improvement in your severely short lower jaw.