Could I get 700-800 ccs injected into each buttock? (Photo)

Thanks for the question. 
In this regard, I recommend you waist and back Liposculpture, getting better curves especially in the waist, improving your body contour.
Finally, I suggested take the fat we get and transfer to the buttocks and hips, to mold them and get better volume, contour and butt projection, is that we know as "Brazilian Butt Lift" (BBL).
Kind regards

It is difficult for me to answer accurately which examining you physically or seeing more photos via Skype.  Ideal candidates for liposuction are at or near their ideal weight with good skin elasticity which enhances results and decreases the risks of complications during and after surgery. Liposuction breaks down and removes the fat that lies just underneath the skin. It’s usually performed on areas that are notoriously resistant to diet and exercise such as the back of the upper arms, the outer thighs, the chin, the bra rolls, lower abdomen, and the flanks.  If the waist was smaller at one time, the waist can likely be reduced to those same measurements or smaller provided the muscular and fascial integrity has remained the same. Harvested fat can be injected into each buttock to improve contour and projection.

Hello
and thank you for your question and sharing your photos. Based on these photos,
you benefit from a TT and BBL.  During tummy tuck, extra skin in the lower.half of your
abdomen including the stretch marks will be removed. In addition, typically the
fascial laxity/separation of recti muscles will be taken care of by muscle
plication, giving you a flat abdomen.  Brazilian Butt Lift
(BBL) typically includes a 360 liposuction of the abdomen and
flanks, and fat grafting for gluteal augmentation. Liposuction of the
flanks will narrow down the waist for an hourglass appearance and adding
volume to buttocks in combination with liposuction of the lower back is
intended at creating a natural curvy look.  Basically, BBL removes
the fat from unwanted areas and transfers it to areas that are
desirable.Incision can be placed very low to be hidden under bikini. With
proper surgical technique, belly button can be designed to  be a true
'innie'. Recovery from tummy tuck is 1-2 weeks. Strenuous activity and lifting
heavy weights should be avoided 6 weeks to 3 months post op. I would seek
consultation with a board-certified plastic surgeon for a full evaluation and
advice. Best,
Pejman
Aflaki, M.D.
Johns
Hopkins-trained double board-certified plastic surgeon