what ever you bring it will be wrong if the wind gods aren't in your favour.
I suggest bringing your fav board and sails that way if the conditions are right you will be on the kit your happiest with.
The 2 sails in one bag works a treat it adds more protection to your sails as well i have done this on a overseas trip
I'll throw in what gear i use just to confuse you more
I'm 70Kg my all round board is approx 65Lt's 52cm wide wave board
my sails range from 4.0 - 5.5 Ive just bought a new 4.7 and 5.3 Goya 3d wave sail
and I'm hoping they will be all i use this summer
Sure we get some strong days if your at Lano just hire a small sail for the day but for the most your be glad of the slightly bigger gear
What ever you bring im sure you will have an awesome time WA is the best place on earth (only my opinion)