I'm not sure what you ended up doing with the fans but I have to disagree slightly with something Krish was saying (sorry). When mounting fans I would have all of them sucking air into the canopy and not pulling air out. Fans that are pulling air out will corrode more rapidly due to the warm salt air they're removing. If you've got several fans pulling air in and a path for air to escape you're removing the heat and adding some longevity to your fan motors and bearings. May not be a huge consideration but something to think about.
Mike