The trick to drilling stainless steel is to use a spray bottle with water to keep a steady stream on the bit. Oil will burn off too fast. Water will boil but still cool. You what to use a slow speed with good stead pressure and keep the bit cool. Do this and you will think you are drilling mild steel. No need for fancy cobalt drill bits but you can use them if you like. Slow and cool that is the trick. If the hole is smaller than 1/4" just use the one bit no need to use a smaller then larger bit. You should go at a speed that will produce long peels of metal from the bit not lots of little flakes. If the bit gets hot it will instantly dull and you will have to resharpen it. I like some of the other suggestions for the home made drill guides, good info there.
Capt. Wayne Canning, AMS
Project Boat Zen - Boat and Yacht Repair and Restoration