Having opening or removable cowl panels would be pretty slick! Take your glass cowl and paint it up without drilling holes in it. Then (carnuba) wax it a few times, spray a few coats of PVA on it then glass over the panels you wish to have 'functioning'. What this does is allow you to make new subsections of your cowl from the mold you just created! Take your new mold, wax it a few times and spray PVA on it a few times. Now lay down your glass for the replacement parts you will need.