Brazilian Butt Lift - Will 350cc Each Side Make a Difference?

It is difficult to answer this question without having an idea of your body shape, weight, height and problem areas. Some people have very limited donor sites for fat transfer, which limits the size of augmentation. However, it is preferable to use the fat you are having liposuctioned to throwing it away, if you are interested in body shaping with fat transfers. Like most things in plastic surgery, there is no absolute cutoff or guideline. However, if you have very loose or poorly elastic skin on the buttocks, it may be more difficult to get a firm, raised look to a buttlift with small volumes of fat.

I do believe fat transfer is far preferable to buttock implants for augmentation, however. I think the implants feel too hard, are difficult to sit on, and have a much higher risk of infection.

If that is all the fat you have to work with, then that is better than throwing it away. It is also better than having buttocks implants. Implants tend to feel and look fake and have a very high complication rate.
As far as the fat volume, I have placed much more than that in many patients and gotten beautiful results. I have also placed less than that in a few patients with very nice results.
The nice thing about the Brazilian Butt Lift, when done by experienced surgeons, is that it can give you a Beautiful shape to your figure, not just enlarge your buttocks like implants do. This is due to taking the fat out from the correct areas as well as placing it in your buttocks in a way that it survives, enlarging your buttocks. It is this combination of the correct fat removal along with getting the fat to survive that makes the Brazilian Butt Lift so dramatic!!!