Practice piece for FM quilting

I have a couple of pieces in the works, one of which has already been accepted into a show and I'll post about that later. I'm still working on my larger piece, finishing the quilting with hopes of submitting it to Houston later this week. Last night, I did some practice stitching using spirals and 2 different types of thread. I wanted to use 3 different threads, but the Signature polyester, size 30, kept breaking even with the size 100 needle. The picture below shows the different background fabrics with the sulky variegated rayon on the left, and the Signature variegated cotton on the right. (The smaller spirals on the turquoise fabric on the top are different Signature cotton that I decided not to use because it was too red.)



I'll have to work on getting the spirals smaller which is not surprising. Due to my medical issues, I haven't done serious FM quilting in several years so there's lots of rust on these skills. But another couple of practice runs, and I'll be ready to step up the real piece. I'm still trying to decide which thread to go with when I start the quilting on the piece today. The rayon is prettier, but I don't want the background quilting to pop out too much as there's already some quilting elements on the quilt. And those elements are done using rayon so there's one part that says match the thread and the other side that says, use the less obtrusive thread to highlight the other figures. Decisions, decisions...