I use both the 5x7 and 7X12 monster hoops in my Brother Duetta with no issues at all. Just have a big enough table to support the quilt so there is no pressure on the arm which might interfere with it's travel. The earliest ones had magnets that weren't strong enough, but the new ones have a fully magnetized upper hoop and it holds plenty strong. I primarily use warm & white or warm & natural but I've had success even with high loft poly batting.