CSM and roving

Hi,
I am currently designing a 29ft offshore rcaer cruiser. Just a simple question. i assume this boat will be built the first time using a male mould. She will be built in polyester, glass, sandwich balsa. I need to use some CSM between each layer of roving, plus one between the gel coat and the first layer of roving.
What is the rule to choose the weight of the CSM between the gel coat and the outer skin (first in general and then assuming that it will be the finish outer surface, i would probably need a thicker one, but how much?)
And then what rule to choose the weight of the CSM between each layer of Roving?

yhank you for your help.

Adrien

 

Sprayed in gelcoat , some of the better builders will use surfacing tissue in the gel coat , and follow that with light cloth , to get rid of any print thru.

Thin 3/4 oz mat is all that's needed between layers of roving , although the military uses all roving , no mat , in their layups.

Some high buck boat builders use paint , no gel coat for the finest finish.

Mostly it will depend on the laminate sked you need .

FF