Wonderfil thread also makes a 12 wt you can run through your machine called Spaghetti.
another option to get your showy bit to stand out is to do trapunto and heavy backfill which results in your motif popping up in relief. I am currently working on a project that does just that and the resulting motif really pops. Edited to add, the backfil is done in a highly contrasting metallic so that also adds to the effect.