Is it me?... Quite possibly it is, as i'm an old fart currently writing from the retirement home for the terminally bewildered.
First you state...
...with an margin of error of less than 5mm.
Then you write
...positioning of the holes is completely random
Any chance of a bit of clarification so that my ageing brain can come up with a solution
Quote: "There is a theory which states that if ever, for any reason, anyone discovers what exactly the Universe is for and why it is here it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another that states that this has already happened.”... Douglas Adams 1952 - 2001