It depends on a few things.... Are you going to vacuum bag the part? what weight of carbon and glass are you going to use? Will the glass be woven or chpped mat? If you typically use a 200gram sq/m carbon or woven glass you would need about 3 layers per mm if you use a vacuum bag. If it is just wet lay it may be a little thicker as you will have more resin on the part as you would be surprised how much gets forced out into the breather stack when you use a vacuum bag..