I've used a few different of the fusible iron on types and none of them have gummed up my needle. Seems like I usually get Heat n Bond light at JoAnns. Although I got some Misty Fuse from a quilt show. Sounds like you have the process pretty well. Iron the fusible onto the back of the fabric and cut out the shape. Sometimes the shape is backwards, then you use a light box to trace your shape. Yes, I have a Teflon ironing sheet to assemble the shapes. I sew with the invisible thread and a skinny zig zag stitch.