Well it depends, are you using a switch mount ? dubro makes a great switch and charge mount jack all in one, as well as great planes , and a few others, if not just use the mounting plate as a guide trace the inside square and cut very carfuly with xacto knife drill holes for mounting screws and done.
Good Luck
Yes you can cut small square hole and enlarge, but I think you will be happier with the prev. mentioned switch jack combos they come with templates and not to expensive.