Just finished a Racing Sparrow 650 all up 1170g with a 630g bulb. Sacrificed a little lightness for the deck finish, I decided to veneer the deck, which added 40g. Fin is a bit soft, 4 layers of 1/32 ply with 2 layers 50g glass, but it works. Glassed the hull with 1 layer of 50g glass and epoxy.
Put it in the water today (31st Aug), fun with tuning and it is fine now. Tracks straight hands off, only 1 click for port / starboard tacks. (+/- 1/2*), very very slight weather helm.
Wow! The deck was worth the extra 40 g.