Hi Russell, I'm good, thanks. super busy with Oulu being European Capital of Culture this year, but surviving.
Thanks for loads of useful information. I've been using optical HDMI on the road for a few years and its great. More sturdy than I expected. The lighter weight seems to help to keep stress off the plugs.
I decided not to go for the 2012 MacPro - with that particular graphics card there's no hardware sync lock between the outputs, so no guarantee that all 4 quadrants would be running accurately. No budget for a M5 Max, so I've ordered a used M2 Mac Mini for the playback into the Saeda. Cable runs are short, so no worries there - all HDMI cables can be the same length.
The projectors arrived yesterday and, at first test, the image is super sharp. and they don't get hot. The only obvious design flaw is that the mounting points underneath look a bit flimsy, and are strangely distributed - I will probably build some mounting brackets out of ply and leave them bolted to the projectors.
So it looks like this is the first video installation project I've made in the last 18 years that doesn't use Isadora at all!