satin is such a pain....
it slips and slides- you can stablize the back- but not the front-
if you choose to incorporate satin .... lots of pins---like every inch- and stitch slowly- if you want your seams to be anywhere close to straight....
once it's done it will be beautiful- but you have to take the time- to make it work satisfactorly- not a fabric to add if you are in a hurry-or impatient