Thanks to all for responding with so many helpful pointers. The Brother Circular Attachment is exactly what I am using. I had pin basted previously. With ideas picked up here, I spray basted a block well and then used the powered digital dual feed foot that came with my Brother DreamWeaver XE to try quilting the circles again. (I had tried a regular walking foot as suggested, but the top feed wasn't powerful enough.) I turned the top feed setting on the MuVit up to "3" and it sewed those circles perfectly without a single pucker and without any puffiness. That walking foot on steroids is amazing! I do, however, need to practice more to achieve a perfectly formed circle using more pointers from my wonderful fellow quilters here.