I suggest you take a set of pictures standing in a neutral position with pictures from the front and the side similar to how plastic surgeons take before and after pictures for gynecomastia.
Put it on your calendar to retake pictures every six months. Make a note of how much you weigh for each...
If you're planning a significant change in body fat in a short period of time, you should wait to have surgery. Your results will be better and you'll enjoy them longer if you have surgery when your weight is stable.
Once you achieve your goal weight you will need some fat transfer to the chest to correct the indentation you see. Liposuction will be performed to acquire a small amount of fat, that fat is cleaned and then injected into the area lacking volume
