I have a brother PQ1500 on a SR2 grace frame. I use different colored top and bottom threads a lot. Here is a pic of the Top and bottom. Orange is top with orange thread, teal is bottom with white thread. Same weight thread. You can see the tension is pretty set so you don't get color on the wrong side. There is a slight peek of the orange on the back but only with the enlarged pic to the naked eye you can't really see it.