When I was about 21 I was making a CD cover for a CD I made of different songs I liked. I did the artwork myself and decided to print it out. But I kept getting the size wrong either to big or to small.
So I taped with clear tape the case to the monitor and used paint shop to size it into the case. And 100% size to make sure it would fit. My oldest brother sees this laughs and said it wouldn't work and I was an idiot. I printed it infornt of him and cut it out where it need to be cut. It fit perfectly. His jar dropped and I just smirked lol.
You can also put painters tape over the holes and mark them. Remove the tape from the item you are hanging and put the tape on the wall; drill, remove, hang.
So I taped with clear tape the case to the monitor and used paint shop to size it into the case. And 100% size to make sure it would fit. My oldest brother sees this laughs and said it wouldn't work and I was an idiot. I printed it infornt of him and cut it out where it need to be cut. It fit perfectly. His jar dropped and I just smirked lol.
I'm not sure I want to think of your brother dropping his jar lol