If you have access to a router table with a lift, "sneaking up" with gradual increases in both the depth and width is the way to go. If not, gradual depth increases, followed by gradual width increases, will give you a better result than trying to find a bit to do the whole thing at once. Think about it this way.. In the time it takes you to drive to a supplier and buy a different bit, you could have increased the depth and width 1/16" at a time and ended up with a very smooth finish with no errors. Working carefully and gradually is always more accurate and safer (!) than speeding through things. Thomas Chippendale's workers in the 18th c. did all he directed with hand tools with no power, and their stuff is good enough for museums. If you are running a production shop, on the other hand, get yourself a 220 volt Shaper and you can get cutters big enough for one pass to do damn near anything.
russmatt, Pa, USA