Thanks for the suggestions and input.
J_Menz, Op 10 no. 2 is an aspiration of mine to play, but I think I'm one or two years away from getting it to be even a mediocre, passable effort. Right now I max out at around 112 bpm, and rather sloppy at that. I do practice some of Blanchet's Transcendental Preludes that make similar demands on fingers 3-5 and also do scales (like the notes C, D, E, D, E, F, etc) where 3-5 play triplet scales while 1 and 2 alternate playing a third down from the lowest note of each triplet grouping, doing both legato and staccato. I do the same with my left hand. Godowsky's left hand op 10 no 2 is surprisingly easier for me than the right hand (I have an odd double jointed index finger on my left hand that bends backwards instead of gripping stably, so I think that has made my 3-5 fingers stronger).
Quantum, I think tone should depend on the piece, but speaking generally I aim for clarity. A good jeu perle is what I'm after. Right now the flow from note to note sounds uneven to me. My partner, who went to university for music performance, claims she can't hear the inconsistency of tone, but it really bothers me. It doesn't really affect my usual playing--shaping a melodic phrase or voicing a harmony I can get near to the sound I want for everything I've played (I don't think I'll ever to faithfully reproduce the sound I hear internally, though), but in scalework I can't achieve anything resembling what I intend--the gradations in tone feels to me like the silhouettes of distant mountaintops--one note too high, another too faint-- rather than the smooth, mostly unruffled surface of a pond I would want. The movements of my fifth finger--rising, falling, curling, extending--give my hand a feeling of imbalance, and I associate that with what sounds to me to be an unbalanced tone in scale and run-work.