It might seem like some extra work...but if you go through the process of clamping it between two blocks and hammer the edge over to make a 90 degree angle before cutting it, the cut will be mostly hidden vs. just cutting to fit. I know the cells by chance happen to perfectly line up with the size of the vent hole, but doing the extra step makes for a better final result. I think that there is a guide on the mnpctech site on how to work with this stuff, and there is a worklog or two here using Home Depot gutter guard using this method (I'm forgetting who posted one). Here's a picture so you get a better idea of the end result...btw, a permanent marker makes a pretty good 'paint job' on this