Going only on your Foucault test numbers and what looks like probably a good edge in the not so good Ronchi image:
In post #132 Foucault Test Analysis program shows for those test readings wavefront errors and Strehl are in the marginally acceptable range. Not that you should quit now, but if you couldn't get it any better it's good enough. a best fit conic is -1.21 or you could say 121% correction.
It shouldn't be too difficult to cut in half the current deviation from a parabola. About 110% correction or .025" +/- .0025" knife movement between zones gets errors in the good mirror, pretty well inside the acceptable range, strehl near .96.
You might do better than that. Maybe not.
Now for a comment of figuring. For now lets look at the sawtooth profile made from percentage of correction. Looking at the graphs, at the boundary between zones you want those kinks, slope changes, straightened out.
Upward changes of slope are under correction, less than 100% of target correction between zones.
Downward slope changes are over correction, more than 100% of target correction between zones.
No slope change is 100% correction between zones.
For a shape like yours where all the slope changes are downward, over correction.
As a general rule, as you stroke whatever pattern you have chosen, there is a central area of the mirror that is always in contact with the lap. The size of this area depends on the maximum overhang of the stroke. If maximum ovehang is 1/3 diameter, then the central 2/3 diameter is always in contact with the lap. For a 2/3 maximum overhang the central 1/3 of the mirror is always in contact with the lap. Whatever the size, that central area always in contact with the lap tends go toward spherical.
That's what you want to do to your over corrected mirror. It's overcorrected in all zones so short strokes have minimum overhang, large central area of the mirror always in contact with the lap. Overhang can be chosen depending on the location of an overcorrected zone.
The 1/3 or less overhang is not enough to generate a significant increase of pressure at the edge of the lap, so even the outer area of the mirror that overhangs usually reduces correction also.
I'll tell you about increasing correction between undercorrected zones later. Maybe you will have some before you finish. Or maybe not.
You are close enough that any single short figuring session could get you in the keeper range.