I have not used metallic thread for a big project but is there any way you could quilt with the metallic thread on the bobbin instead of using as the top thread? Your quilt is absolutely beautiful.

Here is what I do. On the spool of thread I make v's all around the spool with Thread Heaven. And I use a thread net. And I sew with metallic thread a lot. Hope this helps you. Works for me.

The things I do when using metallics is to loosen my tension, use a larger needle & often per wind the thread onto a bobbin to use on top my fancy embroidery machine can be picky .and just cotton thread, matching color in my bobbin. That solved my breakage problem without buying anything else.
good luck & happy stitching.

Getting ready to take a class that involves metalic thread, so do not know if this will help. First lower your upper tension, use the proper needle for the thread, suggested a metafil 80/12 (seems you have that covered), slow your sewing speed down, way down. Your bedspread is breath taking and I love it!

Whitch way do have the spool of thread,I am not sure but it does make a differance.