Pretty scary cutting all of these holes in the fuselage this early in the build. I'd be more comfortable bolting something on rather than cutting something out.
I do know that a square corner could lead to stress cracking, so the corners of holes should be rounded. To do that, I drilled the corners and then connected the dots using the body saw. There is less dust with the body saw that with a dremmel disk, but the line is not nearly as straight. So, a bit more sanding is necessary,
I must have measured that hole a hundred times before cutting. LOL!