As a comparison, the lightest carbon foiler moth hull ever made was 6.9kg delivered. After some time it increased to about 9kg which is similar to what most new foiling moth hulls are built at now in pre-preg carbon and foam (Fastacraft advertise 9.5kg once painted).

My mates and I have built a hand-laid glass foam moth hull which started at about 12kg and ended up about 14-15kg once we made local repairs where it wasn't strong enough (mast chock, transom).

Moth hulls are of a similar size to F12's and these bare hull weights are in the vicinity of what the F12's are being designed/built to.

So I don't think there is much weight to save in the hull structure. Centreboards and rudders are pretty well known so not a lot of weight to save there. Beams - going to carbon is an option to save weight but cost could be an issue (filament wound tube 50 x 2.5 x 1330mm = $350). Not much weight to save in the rig without going to a carbon mast or light sail materials.

High technology and low cost for home builders are opposing goals.

Carbon Fibre Express