So.....aforementioned boob container came in the mail yesterday. It is NOT GOOD. And it is getting returned.
It's supposed to be my "real" size and it still isn't working. I almost started to cry after I put the thing on. It was big, ugly, uncomfortable and still didn't fit right. It was the "Lauren" by Freya in a 36G.
In the last 6 months, I've tried all of the following sizes and met complete and utter failure with each one:
38D (I was wearing this regularly before I tried finding the Right Size)
36DD
36DDD
36G
By process of elimination, I think I'm going to try a 36 or 38F and see how I fare with those. Generally, I'm having 4 problems: gaping at the top of the cups, gore not lying flat, band/underwire digging in and underwire poking through the center gore. With the Freya bra specifically, it was just....huge. Well, huge in the cups but tight in the band. It came almost all the way up to my armpits, all the way around and was just way too...tall...in the front. If I wore even the slightest V neck, it would have shown. For reference, under bust measurement is 37 and bust measurement varies from 42-44, depending on what they feel like doing that day.

I'm currently wearing a 36DDD and it's the best fitting bra I have but it's still not right. The cups feel ok, but the gore is still not lying flat and the band is so tight that it leaves deep marks when I take it off. This goes against what I've read about band sizing!! I read that if the gore doesn't lie flat, you're wearing a size in which the cups are too small but the band is too large. Well.....the cups are constantly feeling too big and the bands are constantly feeling too small! I've tried "balconette" styles and I really like them but it's hard to find ones in the size I need that don't look ridiculous or behave more like a full coverage bra.
Also, the section of the bra where the cup meets the strap does not lie flat either- I can fit 3 fingers between the fabric and my skin. I don't know if this just "happens" or is another indicator that things are Not Right.
I'm about to just give up and start buying XL sports bras for day-to-day use.