I started work on the stays this weekend.  I decided to try the JP Ryan pattern since I've had good luck with them before.  I made a mock up and it fits pretty well.  I need to widen the neckline and  move the straps to the back. Why would she have them in the front, with the ties in the back? That seems so hard to adjust. And I don't think I've seen that on period examples.  But anyway, the rest fit pretty good on the first try.  I also washed and ironed the fabric, which took forever.  Next step is redoing the neckline and another mock up.