I like a lot of Handi Quilter's rulers, but I am totally in love with DeLoa Jones' circle buster and boomerang rulers. These are engineered so the 'innie' and 'outie' side of the ruler will result in the same size curve when used with your ruler foot. This means that don't have to be a contortionist, or keep moving the guide back and forth to each side of the foot. You can use the ruler on the same side of the foot across the whole quilt
https://www.deloasquiltshop.com/collections/guides