was gonna go with a pretty heavy glass schedule recommend a particular weight if you want
YEA -- do NOT use any Glass, if you want it Strong ---AND--- Light !!
If ya haven't shaped the blank yet then :
you said it had a stringer already in the blank ? --- you can make
two more if you measure from the existing one to 1/2 way to your rails
then make a line, and cut the blank from top to bottom Full length
and glue it back together again with + - 45deg stitched carbon or
even a thin marine ply , or balsa, or plane weave carbon on the 45.
shape it first, then cut it and glue it back together with the carbon ; that
way you don't breath the carbon when shaping it. Now a light woven product
can be wrapped an inch over the deck top & bottom to help insure
you never get a Delam, it ties the skins together.
After shaping use the stitched carbon bottom & top for your skins ; but place
50K uni or a stitched uni on the top & bottom of each stinger , ((first)).
Use Epoxy ...
that's the way i would do it --- it's worth the little extra you will pay in materials .