I roundover after I do the contours and have sanded the perimeter sides. On the back side,I go almost all the way to the end on the base side near the neck hump and finish it up with a round file and dowel/sandpaper. Same with the opposite side of the neck penisula on the back side. You want the large radius to taper out to a small radius on the penisula which I do with a small file and sandpaper. It's almost like a 1/16th diameter arc there. I like to use a 1/2" radius roundover bit. On the top side I rout completely around it from end to end. It might be easier for you since it is the first time to rout the roundover before you do the contours.