About fairing and weight
Silvertip QuickFair from SystemThree ships at about 10lbs / gal. A gallon goes a long way; I don't think I've used that much yet.
Anyway, compare this to the weight of the hull at 500+ lbs.
If you add one gallon of fairing compound, you've changed the weight by < 2%.
Still worried? Then remember, you are spreading that weight over a considerable area near the warterline, you are not concentrating it at the tip of the centerboard or top of the mast.
Still worried? 10lbs/gal compares to 8.5 lbs / gallon for sea water. So you are adding something that's rather close to neutral buoyancy.
Still worried? Have a beer.
Oh wait, how much does a six pack weigh?