And no I hadn't seen that article.
I ended up with this type of bluetooth transmitter. It uses Apt-x for less laggy transmissions, but it definitely works better using optical out than analogue (I guess the signal stays digital rather than having to be converted). Quite a few reviews I did see mentioned that throwing a DAC converter in with bluetooth increased the lag noticeably, and suggested you should only do this if you can manually adjust the sound lag on the TV.
As I say, I was kind of stuck with this approach as my first effort at TV shopping (Panasonic) only had HDMI ARC and optical out and I wasn't dropping $1,000+ on two sets of high end Sennheisers that natively supported the optical out. But I probably would have gone with some lower end Sennheisers just for the simplicity of not worrying about pairing etc. if I had started with the Sony and it's traditional 3.5 mm jack.