Do I need a breast lift + breast augmentation? (Photo)

Only a breast lift would be adequate to get you a nice breast shape. You do not need implants and if you were to use 400-450 implants these would be very large and subject to recurrent ptosis

Dear Mimi553,
determining whether you need simply a breast augmentation versus a breast lift can be somewhat complicated. It depends on a number of factors including skin laxity and current nipple position. Generally speaking, if the nipples are lower than the inframammary line the patient will most likely need a breast lift. If the nipples are at or above the inframammary line we can generally get by with just a breast augmentation depending on the size of the implant the patient wants. I often still using implant when I perform a breast lift because it provides more upper breast fullness after the lift. To be sure a consultation with a board-certified plastic surgeon will help determine what the patient actually needs.
Daniel Barrett, MDCertified, American Board of Plastic SurgeryMember, American Society of Plastic SurgeryMember, American Society of Aesthetic Plastic Surgery

It is best to make a decision on an augmentation and lift when you are at your stable weight since you mentioned that your breasts change with weight fluctuation. Implants alone will give more upper pole fullness. They will add volume but will not raise the position of the nipple. I encourage you to meet with a board certified plastic surgeon to discuss your goals for surgery and learn more about your options.