I've decided to add a motion light to the side of my garage that faces the alley. The problem I'm facing now is how to add the light where I want it. Ideally it would be centered with the peak of the roof line, however this means placing a jbox right on a 2x4. I assume this means using a pancake box, but I can't figure out how to get the box flush with the siding. If I wasn't lining it up with the peak of the roof, I would use a cut in box but due to the 2x4 I can't do that. So, I'm looking for thoughts on how to cut the siding to allow me to place the pancake box. This is masonite/hardboard siding and the interior of the garage is unfinished.
Thanks for the help.