Andrus, If your router table has a fence that will allow a 3 7/8 offset for the bit, then you will only need 3 changes of the distance. Make the first flute at 1 3/8 the next at 2 5/8 and the last at 3 7/8 from the fence. simply swap ends with the board after each pass and run the board again. After 3 fence changes you will have 6 flutes with 1 3/8 to the center of first flute and the last from the other side, with 1 1/4 between the other 5. the extra 1/8 on the first distance is used for a 1/8 round over on the edge. Check my math. Also if your fence will not do this, clamp a straight edge on your table at desired
distances. Be sure to use a stop mark on the fence both directions ie. start and end points. Good luck.