For millimeter precision I took it to area near Phule Mandai where lot of people cut designs into wood. There I got precision of 1mm. I paid 10 Rs per hole and it was cheaper to get transported planks there than investing into tool.
I got my speaker baffles cut in same way - these people who cut
designs use hand held router and jig saw tables. Rate was the same
in Hyderabad also - Rs 10 per hole, and pretty accurate.
They are quite skilled, and even made 6mm deep inset/rebate for
flush mounting the drivers.
M-seal epoxy and/or rough file can be used to fix minor issues, if any.