I use invisible thread for applique all the time- I use a small blanket stitch most of the time- once in a while I choose a small zigzag- but never satin stitch- it Is not a good choice for satin stitch- a satin stitch is a very heavy stitch- which I never use for applique- but some people do- with a thread in a coordinating color- since it really stands out & stiffens the applique edge.