im a longarmer and i always use customer chosen thread and batting. i prefer working with cotton over cheap poly they bring me. i use quilters dream cotton batting purchased on a roll i make available for using in my customers quilts. tension is much harder to fine tune on poly. just doesnt grab the thread as well..atleast in my experiences. find another longarmer that will stick with your wishes. if i LA for a new quilter, i will make sugestions and explain why, but if they have their heart set on it, fine by me!