Regular Heat and Bond is difficult to sew through. If you don’t intend to sew or wash the finished project, it will be fine. If you want to sew the appliqué circles down, I suggest using the method where you sew a used dryer sheet of light weight interfacing to the right side of your circle, cut a small slit in the dryer sheet and turn the circle right side out through the slit. If you iron it carefully, it makes a nice circle ready to stitch down.