I use invisible thread on the TOP only when doing SID. I really like it since you can not see top stitching and therefore your mistakes. I use regular thread on the bobbin and it gives a nice pattern on the backing. I have tried FMQ with invisible thread and do not like it. I need to put thread in upright position either in holder on machine or in a cup. Also you need to sew slow so thread does not "whip". Keep trying and you may learn to like it.