Even though it's an old thread, here a few thoughts from an amateur. First corner drill with the largest Forstner bit I own. To connect the holes, I've never used anything but a conventional, fine-tooth jigsaw blade in my trusty, variable-speed Bosch 1022, cutting from the "good" side. Slower, the better. Haven't ruined any countertops yet, and don't even know if my blades are cutting on the up- or down-stroke.
Ah, yes, ignorance is truly bliss!