something to note that i discovered many women (and men) don't realize is cup size is not static across band sizes (sorry if you do know, i just got the feeling that this wasn't clear in the thread above...)
anyway...
the amount of "boob volume" that can be stuffed into a 36C is actually LESS than the amount you can stuff into a 34C. along the same lines, that same 36C boob is larger in VOLUME than a boob in a 38C.
sooooo... 3 women with bra sizes 34D, 36C, and 38B actually all have the same size boob (if they are wearing a properly fitting bra of course), however their TORSO sizes are different.
with that said,
1) @ShoppGirl its reallllllllllly hard (impossible?) to tell what size you will be in the future. on top of that, it's equally (more?) difficult to determine if you will stay that way.
2) i do understand that you have a decision to make (under time crunches and duress, omg) but like everything else on here, its reallllllllyy hard to compare yourself and your outcomes to others cuz, well, you know... but since you asked, here are my deets:
btw, 28D is like a unicorn to find in a retail store...i just get the sister size of 30C (which isn't that easy to find either, but at least better than trying to find 28D!)
i didn't keep meticulous records of my changing bra size during active weight loss, so i can't say how quickly i changed bra sizes. i dont think i even bought a new bra during weight loss phase, just kept wearing ill fitting ones or none at all, ha.
not sure i was any help here, but it there is anything to take away from this data of my sample of ONE, is that if you shrink proportionately as you lose weight, you will stay the same bra size (remember 28D has same boob volume as 30C, just smaller torso, which has nothing to do with implant size)...now, will you shrink proportionately? who even knows.
3) lastly, in my insignificant opinion (i mean i am just a stranger on the internet), if it were me, i would opt to err on the side of smaller vs bigger. i can always wear a padded bra if i wanna go bigger afterwards, but not much i can do to make a set too-big boobies smaller.
good luck! ❤️