me personally what i did was just measured from the edge of my bit to the edge of my housing 6.5cm, outlined my holes at 6.5cm from the cut and quickly clamped down boards along those lines just close enough together to not allow the router to go between them. the extra time was less that 10 minutes for all 4 sticks, and they all came out neat and perfect, i think it was worth the extra 10 minutes.