I had not intended to do a further post on this, as I think the previous five posts summed up the past two years of toil quite well. Then it dawned on us that a small video demonstrating that the dulcitone not only looked good now but sounded pretty good too wouldn't be such a bad idea.
The last few percent of improvements were some of the toughest to achieve with meticulous note taking about what element or component was hindering performance. Multiple sweeps of each key was required and along the way certain concessions and resignations were required when margins of improvement were, for now, outside of our grasp.
So, there are still some forks who's tuning had drifted somewhat and some keys and hammers are a little "lazy" in returning to their default positions which can create the odd dead spot when playing. I would imagine some bespoke overhaul of some hammers or the sourcing of similar hammers from a grand piano supply might be an option in the future, but for now she has taken place of pride in the domicile-cum-studio and has already started contributing to some new recordings. So watch this space!