I generally use Bottom Line for English Paper Piecing work, but I have used Masterpiece and King Tut on my machine. I would go onto Superior's website and go under Reference Guides.... it's up in the right hand corner above the sign in button. And then click on the 'Thread Reference Guide - Home Machine' link. That will pull up a chart with all brands of threads listed with the recommended bobbin thread, top tension, and needle size (and other info!). I've used it before when I had some issues using Masterpeice and KingTut together and just changing the needle made a huge difference. That might be the best place to start and then tweak it from there to suit your machine.