PORCO ROSSO RULZ! ! ! ! !
I loved that movie! Every modeler needs to see it at least once.
I'd suggest you make the struts from solid 3/16 aircraft alloy that is filed/sanded/polished to a fat'ish airfoil shape in the exposed areas. I'm guessing that this will put them at about 1/2 to 5/8 inch wide. With 4 of them this should be a decently solid mounting that can withstand at least some rough landings and the odd wing float bounce. It'll also mean that the buried areas are beefy enough to take the mounting holes and hardware. The smaller diagonal braces could be from 1/8 treated similarly. These really should be a T4 to T6 alloy as even at this size milder alloys would bend like a wet noodle. But the T6 stuff has a far higher yield point so it should be able to flex without taking a setting. IF the model is any larger than 600 sq inches then I'd suggest doing the same things but with 1/4 and 3/16.
Using thinner metal with wood fairings is just asking for bent struts IMHO. If you want to go that route then I'd suggest 1/8 or even 5/32 music wire with wood fairings. It needs to be this heavy to take the flex out and avoid a lot of engine vibes shaking things up.
Best of luck with your Rosso Racer.