A few days ago the weather was cooler than normal so I tried the bra + binder combo aaaaand while it was not as horribly uncomfortable as I feared, it did fuckall for the back pain. My conclusion is that the main problem really is my terrible posture interacting badly with the binder forcing me into a straighter position, so fixing that is a priority. I’ve got a perfectly good set of exercises to do that will help, I just have to actually do them regularly. :P
Interestingly, it wasn’t really an issue yesterday despite the 9km walk, and my binder was downright comfortable for a binder. I was a little sore under/between my shoulderblades when I took it off, but that was it. I did also feel like I was about to fall out of it at any moment, but as far as I can tell nothing actually shifted, so I think it’s feeling the way it’s supposed to feel.
I should be better about alternating them though, so one doesn’t get more worn out and the other doesn’t feel too tight whenever I wear it.