I ferried a C152 from NSW down to Hobart a few years ago via the Wilsons Prom - Hogan Is - Deal Is - Flinders Is route. I waited for a big high pressure system to park itself over Bass Straight so it was CAVOK the whole way and I could cruise at 9500'.
One bit of advice a yachtie gave me was that if I survived a ditching I would die from hypothermia in the icy waters of Bass Straight by the time someone came and fished me out, so I ended up wearing my 4mm steamer wetsuit under my clothes for the overwater flight. This had the added benefit of keeping me comfortable at 9500' as the 152 was a little draughty and the heater didn't work!
It was a great flight, magnificent scenery and the refueller at Flinders Island was friendly and helpful.
cheers
Jex