For you enjoyment, I submit this nice 6'1" single fly rounded pin tail twin fin shaped by Steve Griffiths of Emerald surfboards Taren Point (near Cronulla). According to surfsearch Steve left Emerald in 1979 although I would have guessed its age at 80/81.
It has a nice 'Lighting Bolt' inspired spray, pin lines and multi coloured laminated fins.
I love all twin fins but round tails always look a little weird to me, like twin fins can only work on a swallow tail.
I'll take it for a surf and let you know how it goes.