It's been about 12 nights. Getting rid of side sleeping has definitely reduced my symptoms by a worthy degree and I wish I had done this much earlier.

I had tried this before, but didn't have the will power to make it happen. However, when switching from sleeping on my left to sleeping on my right caused right-sided TOS symptoms, that really convinced me it had to be fixed.

The first couple nights were the hardest but it got easier after that. I still make use of that "half and half" position, where my legs are to the side, but I rotate my upper body back. I use an extra pillow under the opposite shoulder so I don't have to rotate the whole way.