Looks like there will be plenty of wind and waves to greet you on Saturday anywhere between Yallingup and Margs but it mighty be worth heading straight to main break (Margs) as that looks like you best chance to see it really firing, your gunna have a ball.

It is quite a drive to Denmark with probably less chance of wind and waves so not sure if it is worth it if you only have five days, but it is a nice spot and a nice drive,
not much to see between there and Perth though.
I find a SS springy is enough for me around the Margs area at this time of the year but plenty of crew still wear steamers, if you are going down around the Denmark area then yep pack a steamer for sure.
Enjoy