Well done! You can't get much better than that!

OK, so the next step Hakki is to spread the temperament out of the temperament octave, while still keeping its basic character.

For me, this has worked well until the last treble octave or so, where, if you choose, as I do, to use 2:1 octaves rather than pure 12ths (which is what I use, in general, for the rest of the piano) or something else, the 2:1 octaves destroy any temperament, but sound good.

Really? I would think expanding a temperament with P12s (which I also do) would move the temperament around the circle of fifths each 12th, while tuning with octaves would retain the temperament.

This idea of extending a temperament via 12ths vs octaves was interesting enough that I tried doing a little math to see what's going on.

First, here's a picture of the "Railsback" curve of a typical stretched tuning with the Thomas Young unequal temperament applied to it:

The temperament is being expanded by octaves, and the octaves are stretched for inharmonicity. But the temperament stays intact in each octave, which you can see by superimposing the tuning curves of the 2 neighboring octaves onto the F3-F4 temperament octave.

Just for fun, I also tried shifting the tuning curve by perfect fifths instead of an octave to see if it still kept some of its personality. It did. So one cycle around the circle of fifths and the temperament hasn't actually changed that much.

The last test was to shift the tuning curve by the perfect 12th (octave + fifth)

As with the 5ths, there are differences, but the spikes and valleys are in roughly the same places, so the intervals will generally sound similar outside the temperament octave.

So I think Jeff/UprightTooner is correct that you'll be altering the temperament each iteration, gradually cycling it around the circle of 5ths, but perhaps these differences aren't as obvious as you'd expect because each iteration is fairly similar to the previous. Of course I think my little analysis is an oversimplification, since I think tuning outward by pure 12ths will be doing weird things to the beat rates of the 5ths contained inside those 12ths... it kind of makes my head hurt thinking about that.