Used a step drill for all switches on two panels. If you are drilling several holes in a line, a step drill in a hand drill can walk. Use drill press and clamp your panel!
A drill press is overkill, or at least a substitute for good workmanship, and nigh-on impossible to use unless the instrument panel is on the workbench and depopulated of components.
A better, more workable solution, especially for retrofit scenarios, is as follows.
1) Mark hole locations (I use blue masking tape on top of the instrument panel to lay out hole locations and to provide protection against tool marks)
2) Center punch hole locations
3) Drill through center punch marks with sharp/new 1/8" or similar twist drill
4) Use these holes as pilots for your step-drill/unibit
NOTE: when doing this kind of work in a retrofit with the panel in the airplane, aluminum chips are a problem. Save yourself some trouble by taking 2" blue masking tape, folding it along its length to form a 90 degree angle, like a piece of angle iron. Stick one side of this to the instrument panel below where you will drill a hole, leaving an inch or so lip of tape sticking out toward you, with the sticky side up toward the hole being drilled. Do this on the back side of the panel, too. You'll be amazed how much swarf will be captured in the glue of the blue tape. It also helps to have a vacuum cleaner nozzle over the back side of the hole being drilled to prevent swarf from spreading around on that invisible side of the instrument panel.
I've done hundreds of instrument panel holes this way with very good results.