I've used a basic drill stand with a normal drill to do it very well, just setting it up to drill through the hole at the bottom of the stand. Use the bridge holes as a template for marking the positions on the top, then drill the two E string holes all the way through and the four inner holes 2/3 the way though. Then turn the body over, use the two E string holes to line up the bridge, then again use the bridge holes to mark the 4 inner string hole positions, and drill those through about halfway until the holes line up. That way your top and rear string holes should be in a nice straight line.