I was in Marg's over xmas new year and kited both Gnarabup/Prevally (the boatramps bommies) and main break.
Best launch for Prevally seemed to be about half way along the beach - if you go down Mitchell drive and park in the carpark opposite Georgette way, you can walk over the dune with gear and launch from the beach in clean air and no reef on the shoreline. If you head directly out from there you have a pretty clean channel straight out the back between the breakers on the outer reefs.
I scored pretty steady 20-30kn seabreezes (when it was on) but was only there for 2 weeks, 8m switchblade II was good for most days but could have used a 7m on the really windy day (see
www.seabreeze.com.au/gallery/gallery.asp?imageid=8550).
As Gasman said, the waves on the boatramp bommie itself were a bit ordinary, plenty of size but there are assorted bits of dry reef popping up all over the place and the wave tends to section a bit - still a fun spot to kite, but take the time to have a look at the lineup and the reef before charging over the shallow bits. Main Break is of course a beautiful wave but the euro poley's were swarming all over it by mid afternoon with lots of agro so wasn't so cruisy, best time to kite there seemed to be just after the seabreeze kicked in around 1-2pm and before the crowds got silly. The launch and landing spot at mainbreak is pretty dicey, I'd watch someone else navigate it first before trying it for the first time.
still a fantastic place to kite, NQ is a little bit spoilt for me now!
have fun, Andy.