Thats funny, I think your close on that all right, 16footers are big Bastards, Im fairly sure I saw one in the Ocean off this bay I know at Coburg, that would be 19-20 foot, head as long as the Cruiser, not as wide but, & looked like a large boat in the water !

Maybe two others near as big or more one from the plane when doing recon for Buff areas along the coast at the mouth of some big river & one at Victoria River passed Timber Creek on the Horse or Little Horse River, he was huge but hard to see in the muddy water, ate horses & Scrubers like chicken snacks !

But agree the ones I see the skulls of are all around the 14-16 foot models but im told off 18-20 footers, grow after Death like you said ! LoL