What I would do is mount a 1/8" drill bit (carbide?) in my drill
press, set the depth stop to allow it to cut through the copper and
not the board under it, and have at it. The drill will center on the
hole so the work is fast. Sounds like a 5 or 10 minute job.
But, of course, you do need a drill press. With a good depth stop,
not the cheap, clumsy ones that the Chinese imports come with.
Also, Vector makes a tool that is just for this purpose. It is used by hand.
http://www.digikey.com/product-detail/en/P138A/V1056-ND/7642It will take more time with this.