I had some bamboo singlets that I found at Target. They were very soft and great to wear under front opening shirts. I wore leggings and oversized shirts a lot after surgery and even during chemo. You want comfy easy to put on clothes.
Once the drains are removed I found ahh bras (from Big W) comfortable. Some have pockets with removable foam inserts and you can put your soft form that you get from Berlei into these. (your breast care nurse should organize a free bra and soft form from Berlei for you)
Best of luck for your surgery. I just concentrated on the thought that when I woke up the cancer would be gone. The rest of the treatment is just extra insurance. Take care. Deanne xxx