I have. A sweet 16. I use superior so fine 50 in the bobbin and sometimes on top, especially when I’m looking for a more subtle effect . I found the machine works really well with Magnifico with sofine 50 in the bobbin.when I want the quilting to stand out a bit more. These are both polyester, magnifico is easier in my machine.
auriful cotton 50 works well on top and bottom. . Better even than sofine in my machine.
my sweet 16 is more finicky about tension adjustments than my Janome 6600. After a little practice I’ve been able to use any thread, including superior metallic with sofine 50 in the bottom. I have a lot of sofine 50, auriful 50, and Magnifico.
ive also used a variegated cotton YLI thread that was beautiful but linty. Haven’t tried my king tut but I bet it would work well. Make sure you have the appropriate needle for each thread. This really helps.
hope that helps. Have fun.