And it is more complicated even than that. I am a small busted woman and yet the best fit I can get is 34D. The 34 makes sense, underbust is 33. The D is what I measure but most have too much room. I still need that size because the circumference of the boobs fits in that wire; any smaller is too narrow.
I think bras need 3 measurements not 2. I need band 34, wire size D, cup capacity closer to C. And there are plenty of women in the opposite situation too, with more projection but smaller circumference.
So the non-standardized sizing is a workaround for that problem.
You are talking to us here, now. I know you do rock climbing and weight lifting. If you have friends, you talk to them too. It's not different from that. You are doing it already. There's not a formula.
What friends can do is tell their friends you are a great guy and introduce you to other people. That's what networking is, the same way you network computers, you network human relationships, by connecting them.