I checked my dimensions against the dimensions in Netfab. They all seem pretty close other than the holes. I am assuming that it is over extrusion like you said. I just to make things easier, I am pounding a 3/4″ spade but into 23.2mm. I will then clean throw it in my drill press and drill the holes to size. I think that this will be more accurate than sanding with a dremmel.