YES go for it!!! I would allow the patient to chose her desired size. And the expansion looks great...
... but that doesn’t necessarily mean they won’t look good. It
looks like your expanders have worked well to set a great foundation for a
successful surgery. Yes, an 800 cc implant will be smaller than the 900 cc
expanders, but remember that the shape and profile of the implants will be
different from the expanders as well, and more like a natural breast shape. I
think it’s likely that you’ll have a very nice final result with great
projection and fullness, even if your breasts are slightly smaller overall than
your pre-surgery figure.
is very challenging with implants and the largest off the shelf implants I know of is 800 cc's. And NEVER use saline in alloplastic reconstructions because they will be very rippled and wrinkly. If you really want big, you may have to resort to using your tummy tissues (assuming half your tummy will create the cup you want) to do this.
Without an exam in person, it would be difficult to tell you what size implants would be best for you. Good luck in your future surgery.