i've done two with interfacing: one with a flannel backing - summer quilt, yummy! one with lightweight batting and a corduroy backing. that was SOME mistake. it was almost impossible to quilt and i thought my wrists would break. at that time i did not have the longarm. that one was queen size. it still gives me a headache to think of it. BUT it is my ds favorite one when he visits here, and he always asks for it. it pins him to the bed with his wife. LOL!