This 500,000 thousand drill holes is a perfect excuse to laser cut out of say 6mm (not MDF) and laminate.  Maybe the second layer a thou of a mm bigger diameter in case not 100% alignment...
The way the number of holes keep increasing, your next one would require 5,000,000 plunges.

My final suggestion is to teach them all Canasta or 500 instead... before the 500 becomes 5,000.

If your first cut is too short... Take the second cut from the longer end... LBD