I have a Sweet16 which is the same thing as the Tiara. I have used it with all kinds of thread ranging from 100 wt. Invisifil by Wonderfil, metallics by a variety of manufacturers, King Tut 40wt.cotton, Isacord Poly, Wonderfil's 12wt. Spaghetti, etc. I've not had any problems with any of them. The main thing is to get your bobbin tension correct and then adjust the upper as needed for the piece you are quilting.
And always check your tension using the same combination of threads, fabric and batting sandwich as the piece you are going to be quilting.
Rob
Last edited by rryder; 09-06-2019 at 01:36 PM.