Ask how many your surgeon does a year. If they do less than 25/year, I would be seeing someone else. This is highly technical surgery with great rewards but also great risks - it's a 6-8 hour operation (with an extra hour or two for the mastectomy), and the risks include not only losing the entire transplanted fat, but also some of the fat melting away so that you are left with less volume than you had hoped for, or asymmetry that needs further surgery later. The best results come from those who do these a lot.
No one can comment on how much volume you will get except your surgeon - everyone carries their fat differently, even for similar height and body weight.
ETA - if it was only one side, then a c cup might be feasible, but women rarely get as much as they are hoping for with bilateral reconstruction, as the tummy fat is shared between the two. You may find that if people are already suggesting you might not have enough tummy fat for this, then you may struggle to get a big A/small B cup. And putting on weight temporarily isn't an option - the fat will behave as it did where it was taken from - if you then lose the weight, it will be lost off your new bust as well.
As others have said, you may decide that such a major operation is not worth the effort for small returns. Don't underestimate implant reconstruction either - implants (whether doe for reconstructive or cosmetic reasons) are rarely a lifetime 'purchase' and usually need further surgery down the track.
This is why, as PPs have said, many women choose not to have reconstruction in the first instance. And in fact, the most satisfied women are those who have the reconstruction later - after they have lived without it for a period of time THEN chosen to go ahead. No reconstruction will look like the breasts you have when naked - the best they manage is to fill out your clothes a bit.
I am sure your surgeons have talked to you about this at length, and it is a very very personal decision - but it's one YOU have to put your body through and then live with. You should proceed with reconstruction, by whatever means you feel right, only if it's something YOU want to do and understand the benefits and downsides of - not because your husband, your sister, your breast care nurse, your best friend, your oncologist, your neighbor, or anyone on EB tells you you should or shouldn't. Take time to speak to people, understand that can be achieved and its limitations, and then decide.
Edited by Fright bat, 01 September 2016 - 03:50 PM.