Been listening all night. Don't want to stop.

[supaDean]

Your setup is actually very clever. Audio routing within the SHD Studio allows you to send L and R to separate outputs. I researched a solution like this for Phantoms (to skip Dialog and Spark) a few years ago. At that time there was no (good) way to do it. If the SHD+Dirac existed back then I'd be a Phantom owner myself today!
Some Toslink implementations can support 192kHz. The main optical on the Expert amps and the Mutec for example. And the 'big' Phantoms... I do not think high sample rate is the most important, however. My current setup is limited to 24/48.

I know I can send 24/192 over Toslink, but there's a cable length stability issue on long runs (from what I've researched), so 24/96 has been the safe norm. I suppose all Phantoms could have been designed to receive 24/192 over Toslink, but 24/96 is safe. Anyway, I don't get hung up too much on these numbers.

The routing on the SHD is excellent. It allows for a great crossover, whether bi-amping speakers or for subwoofers. Or send a stereo signal to a headphone amp via 3 and 4.

As an owner of a pair of Devialet Phantom Classics, I'm fascinated with this set-up.  It might be obvious, but I can't tell - are you using two of the SHD outputs so you have separate L&R Coax SPDIF / TOSLINK runs to each Reactor?  If so, how have you paired them / synced them?  Or do you have a single Coax SPDIF / TOSLINK feed going into one of the Reactors and you've stereo paired them via the Devialet app?  Very, very interested to know as I would love to pull the trigger on the SHD Studio as it seems like just the solution for room correction.  Any other advice on this would be greatly appreciated!

I'd suggest downloading the SHD manual and familiarize yourself with the Phantom Reactor's operation, as there is a learning curve to setting up the SHD. And, from what I understand there are differences between The Phantom Classic and the Phantom Reactor. There is also a useful miniDSP SHD online forum. I'm not on here often and unfortunately haven't a lot of time available to go into any setup detail as I'm a frontline worker. Cheers.