Bruce I’d hasten slowly with these vents. It’s too easy to bugger up a functional vent, and the drag difference might be bugger all. (I’m more concerned at the risk of vent location to your eyes). I fluked a good setup with my first (thin vinyl hoses to top of wingtips, with lots of tiny vent holes drilled thru. The vortex airflow suited the vent site.
Years later, trying to improve streamlining, put in larger vent hoses, exiting just under wing tip. They caused no end of problem, until it was pointed out me that the vortexes were sucking air out of the tank.