www.makanifins.com/collections/windsurfing-weed-fins/products/ahi-thruster-weed-wave-windsurfing-fin

Got a set of these AHI thruster for 10 / 20 for 92 Goya surfwave and 11/22 for 105 Fanatic freewave thruster

The weed might be different in WA (we get ribbon weed and lumps of lbrown weed after storms in SA) but these things work a treat - even when there's no weed you wouldn''t realise they were weeides - no issues wave riding either

Cheers

For wave sailing a normal wave fin will be OK in most locations, but I make mine with a decent rake at the base. It helps with cray pot ropes and floating weed.
For flat water, I have about 3 or 4 different weedy designs, for different conditions.
If the weed is growing all the way to the surface you need a delta type design, very low aspect ratio and rake at least 50deg. The tribal delta is an excellent example. If the weed is only on the bottom, you can use a more efficient curved fin, low angle at the base high angle at the tip. If there's just floating weed, then a straight 45deg is fine. If you're coming all the way to WA, it would be a pity to miss out on the weedy dead smooooooth experience. There's something very special about doing 30+kts in absolute glass, all you here is your wake raining back on the water.

Makani makes a couple of weed freestyle fins which are well regarded on the US east coast where they get a lot of ribbon weed.