You should use a metallic needle in your machine. I would probably use a thinner thread in the bobbin that matches the color of the metallic thread, and yes, you will probably have to adjust your tension & perhaps your stitch length. Pay attention to how the thread is wound on the spool - you pay have use your spool pin.

I'm guessing metallic for your Poppies??? Pretty.....

Maybe for the poppies, but definitely for the ALS donation quilt. I wanted to add beads in case it's used as a wallhanging but someone might want to use it as a wheelchair lap quilt instead and beads can make a quilt hard to launder. So metallics seem like the right way to go. I could do that part by hand but if I can do it by machine I will.

Increasing the stitch length is a great suggestion! Thanks!

A washable shiny rayon thread would be much easier to sew & give you that pop & shine, and it is available in many colors. You could also dress it up by adding a narrow flat braid. Metallic thread can be temperamental ~ especially when you are in a hurry :).

If they still make it I recommend YLI. I used to get it from clotilde but I don't see it in their current catalog. I have used different kinds but nothing compares.
I also like YLI bobbin thread when using metallic and a microtex needle. MHO>

Lots of good recommendations above. I have used metallic thread for quilting but didn't do free motion. I think you will have better results if you use a walking foot and some kind of straight or decorative stitch on your machine.