If i had a new hull i would put the mesh on the outside for looks and leave them closed
I have had water come in through them in very rough sea use when the boat was at standstill.
I cut them out when i was using air cooled chainsaw engine, and was going to add scoops to the ducts to cause ram air effect and
use ducting inside to deflect exactly where i wanted it.
(when i say ducting,i mean the flex off the wife's vacum cleaner )ha ha
I do like the look of the ducts, but then i also like scoops. depends on the boat i suppose.
your boats do have a nice finnish on them, and to look good in black, they must be good.
you can get away with a few flaws with white, but with black you cant hide anything
phill........