What is the diameter of the general opening of the FPC board

FPC Flexible Circuit Board Manufacturers Processing Index and set the line width requirements, General Multilayer Board through the hole diameter above 8mil, outside diameter above 16mil. Make it as big as you can, but not too big. The drill holes in the bottom of the BGA are usually 8mil in and 16mil out. The rest of the place is 12mil inside 28mil.