Ah, a man after my own heart. Tinnie, WS gear, bikes...
Fun flatwater in the bottom lake in a Nth, Nth easterly, launching from Stingray Point, just past Angophora Drive. There's a little track on the right just past the pedestrian/bike path sign.
Take the tinnie across to Goodwin Sands to the speed strip in a southerly.
Didn't get to wavesail, but I expect Bastion Point would be pretty good.
You can sail across to the bottom lake from the foreshore camping ground, but there's heaps of sand bars, and it's pretty hard going until you get to deepwater on the north side of Rabbit Island. Don't do what I did and slash your foot open on the razor sharp oyster shells (although the local doc who stitched me up was, er, very nice).