I prefer a shaped rest for any bowl. but the straight rests work on platter type shapes. I did see some one, can't remember who, when he turned the bottom of a shallow bowl would 'reverse' the straight tool rest, so instead of pointing inwards from the turner to the center of the bowl, it pointed inwards from the transition area of the bowl to the side away from the turner. Not sure if that makes sense or not. Using a straight rest on shallow bowls generally has the rest at an awkward angle for going from the transition area towards the center of the bowl.

robo hippy