Forgive me ... I've been focused on my results on cis calculators and charts and completely forgetting what I
actually use daily...
On the cis charts/calcs I have about 2" difference which comes up B/C on those charts but it's important to note—sorry I didn't say this before—I tend to actually go either braless or wear bralettes. At my particular stage I find bralettes to be particularly friendly... with bralettes, the right size is really about band size where any cup or cup-like area has enough to hold my current size.
Tonight I went into my storage bin of clothes I don't actively wear to get out 40B bras I picked up years ago... they are still too big in the cup.
In my drawer of active clothes I have 40A bras which fit perfectly... but I rarely wear bras like that (almost never) ... usually I'm first braless, or if wearing a see-through shirt I wear an M or L bralette or cami depending on brand. The goal there is really about not being naked in public more than control. Otherwise I'm braless which with the right top looks better because it obviously doesn't have the subtle "binding" effect.
I think there must be something different in the cis-sizing charts and methods, or maybe I'm measuring incorrectly... but I've done it tons of times and always end up with that 2" difference which is really the key that seems to select B/C.
I can't be sure about this, but I'm under the impression trans-women who start HRT tend to have breast growth which is further apart (wider cleavage) for various reasons. I wonder if, for that reason, the area of the measuring tape becomes larger on the breast because the breasts are further apart, perhaps pointing more widely outward than closer together. I really don't know... just thinking aloud.
I got the idea of a bralette by shopping in the store... it's amazing what happens when you transition out of that petrified "online shopping only" mode.

Once I started going out and shopping I got great ideas from the very caring people who helped me.
If I simply throw out all the calculations and measurements, I can say the growth is impressive to me though I know it's not There yet. I wear some shirts which look better than others because they accentuate the size I have now. In other cases, it appears as if not as much is there... this relates to the shirt, its color, how tight/heavy it is, etc. That's why I have some fav t-shirts.
I think this is all to say, while cis charts seem to have me at B/C, I feel like its realistically an A and I tend to wear A-like things... and 3 different 40Bs I own still do not fit... I estimate there's a gap of about 0.5".
That's what I should have focused on in my earlier post, not my current measurements per cis charts... I have just been so impressed with my changes there so far that earlier I just got focused on measuring my current size according to the cis charts and plumb forgot to share what I actually use/do day to day.
I plan to get implants but I'm only at one year into HRT, need to wait about one more I think. That will be a great day.