I ordered some more boards from this shop: they look the same as the one I described in my previous log entries. Spare "D882" transistors and TL431 chips are also at hand.
Now I need to figure out how to decouple the feedback path from ground in a way that's easy to do and that doesn't look to kludgy. I ordered small diamond cutting discs which might be the right tool for this job. Let's see what works best.
Edit: this will be a bit slow as long as no one "pulls" and neurology provides stuff like this:
Check this out for some of the most exciting research since the discovery of neurons: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4932105/