We highly recommend M8 Torx titanium hardware for foil sets, especially on the major load bearing parts like mast to fuselage, or fuselage to wing connections. Stainless steel corrodes much faster than titanium, and will easily strip star (phillips) or hex heads.

For wing sizes, generally speaking as you increase the aspect ratio and the front foil wing gets thinner with a wider span, you can go faster, but you need more speed to get up on foil, and the extra span makes it tougher to turn.

Medium aspect wings have a lower lift speed making them easier to get up on foil, especially in marginal winds when winging and are easier to turn, but lose out on top end speed.