I have a different model boat, but the rod vang did keep the vent hatch from opening very far, and the rod vang was standard equipment on our boat. There are so many sailing advantages to the rod vang that I wish I had put one on our prior boat.
FWIW, when we replaced the vent hatch a few years ago, I did orient it so that it opened to the rear.
This also reduced the number of places that a wandering wave top could invade the interior when sailing in chop.....
We learned long ago to dog the big forward hatch and close the two forward ports when under way..... it was a wet lesson, as I still recall with a smile!
Loren in PDX