Have you had your preop yet? I didn’t have Ms Lutz but when I went to my preop with the nurse she gave me a few recommendations.
Asda and M&S do good post surgery bras and I heard there are some in the sales at the moment. The M&S ones have a zip too which is super handy! I was told to go up a back size (to account for swelling) and up two or three cup sizes but I guess it depends on what size you’re having (I had 325s)
I ended up getting a couple of Macoms which have expandable cups so you only need your back size and some M&S ones in a couple of different sizes to try.