Hi Leman,
Windguru is a good indicator of likely conditions at Sandy Point:
www.windguru.cz/15753 You can use Mat Robertson's correction found under "Options" (top right) to correct for extra strength when there is SW in the wind.
Or you can also use the BoM site:
www.earthsci.unimelb.edu.au/~awatkins/bay.html- and under "forecasts" go to "BoM 7-day wind forc" to see what fronts are coming through.
I haven't sailed on the ocean side but I gather it is best in a cross or cross-offshore wind. I have surfed there and it is a beautiful gently sloping beach without rocks.
The inlet is best for speed in a 20knot or more WSW wind on the outgoing tide but speed runs can also be had on the East bank of the channel when it is exposed at low tide during winds with East in them. There is also Sandy Point B down by the outlet which is good in a West wind, but watch for sharks. The inlet is also great for just blasting about in flat water and if you are into it, doing flicky spinny stuff.
Very importantly, if you are sailing on the inlet and on or near the speed run (along the long crescent shaped south bank) just stay out of the way of the speed sailors who are regularly clocking 70-80km/hr on any good WSW windy day. Very hard to brake or swerve at that speed and a collision could easily be fatal. If you are planing to try the speed run, try to talk to some of the regular speedies about safety precautions and avoiding collisions with each other. In the right conditions it is the most amazing adrenaline rush so worth a go!
Tomorrow looks lousy though - only 14 knots at first light and dropping to nearly nothing by dusk. But in any wind that will get you planing there, Sandy Point is a magic and beautiful place.