It didn't work. In fact, this attempt to merge running a startup with a sustainable lifestyle failed spectacularly.
If you start with the assumption that you want to work, there are lots of ways around the colour codes.
One is "fun work doesn't count", meaning that coding, writing, hardware hacking, and game design happen out of hours - and very quickly, exclusively out of hours.
The next step is then "it doesn't count if it would be less stressful to do it than to stand by and not do it", and that includes basically everything.
Work can displace non-work if permitted to do so, and that becomes circular - if there's nothing else happening in your life, that's all you'll think about.
2) Lack of damage awareness.
I was wrong in thinking that I had an accurate read of my own state.
It may only be by coincidence that this hit me first. Fire Hazard has a bit of a culture around "we're all badasses, and we can handle this", and nobody wants to let the team down.
(I wanted to call this 'Black Knighting' - not knowing, or caring, that you've been injured, after the Monty Python sketch, but it appears that a particularly unpleasant segment of the internet has already started using that term for something else).
We already have the cultural OK to do drastic - even destructive - things to protect the team, but we didn't realise that we already needed to do them.
3) Lack of safe space.
We actually have a system for going completely off work, but didn't use it (due to #2).
It turns out that the permanently-on-call effect, especially combined with extended hours (via #1) is extremely damaging.
The next attempt involves hard work/life separation. My working hours are now generous (8am-7pm), but rigidly enforced. I can't work from home at all. I have separate logins for my phone and laptop, maintaining separation. (As a side effect, I can't get to any of my personal stuff while working). Even my watchface shows either a Fire Hazard flame or a serene blue field.
Once this stabilises, I might add in some more advanced use-cases allowing a morning's focused work at home, or the occasional fire-fighting excursion into the Red Zone. But not yet.
To paraphrase Edison, I haven't yet failed; I've just found another way that doesn't work. We'll see how the next experiment goes.