High Profile Implants for Droopy Breasts?

Without photos or an exam it would be not be possible to give you the best opinion, for example if a lift is needed or not. Here is some helpful information however: It is very difficult to determine the exact size and  profile shape implant you will require to best match your ideal breast image without an examination by a board certified plastic surgeon. Not just any board certified plastic surgeon, but one with many years of frequently performing breast augmentation surgery including different approaches, techniques and implant choices. This is because several measurements not to mention your breast characteristics are needed to determine the optimal implant size to obtain your goals. Without knowing these dimensions it would be difficult to make this determination. For example, the existing base width of your breast will determine, in many cases, the maximal volume per implant profile that you can accommodate. To illustrate; a 100 cc difference may make a significant difference with a narrow base width breast, but much less of a difference if you have a wide chest wall and wide breast “foot print”. Therefore, just because your friend may have a great result with let’s say a 350 cc implant to make her go from a “A” cup to a “C” cup size does not mean that you will have the same result with the same size implant. . Further simply placing implants in a bra to determine the size best for you is not always accurate as the bra often distorts the size, is dependent on the pressure the bra places plus the implant is outside your breast and not under it among other variables. Computer software morphing programs that automatically determine the best implant size can be helpful in some but not all cases (e.g. doesn’t work well in my experience with existing implants, sagging or asymmetric breasts). Using “want to be” photos however are useful if simply provided to the surgeon as I will further explain in the link:

If you have mild to moderate sagging, then implants alone can definitely lift the breasts without mastopexy surgery. They'll give your breasts more projection since the profile will be higher, which means you won't get too much side boob. You can keep them small so they don't look too large. 

High profile implants are less likely to cause "side boobs" than the moderate profile implants which have a wider base diameter.

If you have some sagging, you more than likely will need a lift even with implants.  The HP's depending upon how you are sized will give less side breast and more projection as compared to the others of the same volume.

Probably NOT - but impossible to answer.
When you lose weight (and breast fill), the breasts become deflated. To get them to where they were, or better yet, to a better looking point, the emptied breast envelope has to be filled to the desired point. No More.
SIDE BOOBS - refers to the appearance of full breasts whose base is too wide to maintain flat-fore ward facing footing and projection. Instead, they slide sideways ESPECIALLY in narrower chest and especially pigeon chested women.
So, the question for your plastic surgeon SHOULD BE : based on my chest wall appearance AND the amount of my breast tissue which breast implant (diameter and projection) would best be covered by my breast tissue and stay on my chest wall (without falling sideways)? That analysis is not provided by the measurements you gave us and needs to be looked at by your surgeon.
Generally speaking (meaning it may not even apply to you), in most but the most narrowed chested women, a deflated breast will do better with EITHER Mentor moderate Plus (style 2000) or Mentor High Profile Gel implants (which have a slightly wider base) than a high profile saline implant (either Allergan or Mentor).
I hope this was helpful.