To provide best lift - sub mammary or sub muscular?

I think that the reasoning you have provided on why you want submuscular should be discussed with your surgeon.  I think that the submuscular approach should be used in almost every instance.Try to research this to find the surgeon who consistently produces the
results you would expect. Look at reviews on this site and see who gets the surgery right every time. Find

a board certified plastic surgeon who performs hundreds of breast
augmentations and breast augmentation revisions each year. Then look at
the plastic surgeon's
website before and after photo galleries to get a sense of who can
deliver the results. Kenneth Hughes, MDLos Angeles, CA

Implants do not lift the breast no matter where they are placed.  They simply add volume.  What your breasts look like now should be what they look like after everything has settled, only fuller if you only add implants.   If  you truly need a breast lift then that would require more than just the addition of breast implants.  If you are truly sagging then placing the implants above the chest muscle will result in larger sagging breasts.  If you place the implants below the chest muscle then the implants may sit high on the chest with your breast tissue hanging below them.  The goal is to center your implants behind your breast tissue and areola.  The choice of which procedure would work best for you is something you will need to work out with doctor(s) who can examine you in person.

over subglandular and I would use them over the muscle in only the most unique of circumstances.  As for implants lifting the nipple, technically it shouldn't but by filling the envelope or lowering the implant, the nipple will be 'lifted'.  Some doctors are pushing textured anatomic implants as better than round smooth ones but I would be very hesitant to jump on that bandwagon due to its inherent shortcomings (won't move).  Dual plane techniques have made subglandular somewhat obsolete in my opinion.

Implants do not provide lift to a droopy breast.  Some surgeons unfortunately think that if they put in a large enough implant they can get away without performing a lift and save the patient the additional scars. The result is large breasts that tend to be even more saggy due to the additional weight of the implant.  If the  implant was originally placed under the muscle, it will frequently drop enough to be almost below the edge of the muscle, so whether it was placed above or below the muscle becomes moot.A better approach is to use a smaller implant accompanied by a lift. Often this can be accomplished with a lollipop incision, avoiding an incision in the crease below the breast.  In your case you already have a substantioal amount of breast tissue and merely need an implant to give fullness in the upper pole.It would be wise to rediscuss the plan with your surgeon, and get another opinion before proceeding.

Breast implants are pillow volume. They fill the breast out (forward) but do not lift it vertically on the chest. Breasts that are too saggy (ptotic) cannot be filled out properly with an implant alone. This has to do with where the nipple-areola sits relative to the inframammary crease directly behind it. If the nipple-areola is more than 2 cm below the level of the inframammary crease behind it (upright with arms down), then an implant cannot be positioned properly behind it to fill it out properly regardless of whether it's sub mammary or sub pectoral. After decades of experience and for many different reasons both short term and long term, breast implants do best if they are partially sub pectoral and the best incision to place them is in the inframammary crease. In the sub pectoral position, the minimum size increase of a properly sized and positioned lowest profile breast implant is one cup size relative to the same chest circumference.In my opinion, properly sized and positioned breast implants to not make breasts sag, but breasts can sag without implants so there is no way to know or control whether borderline ptotic breasts will become too saggy in the future.