Hi Rick,
My view is that circuits like the DOD250, that use a diode pair (or trio) to ground on the output, may well be clipping twice. Headroom limitations, dictated by supply voltage and gain used, can result in clipping within the op-amp, followed by diode-clipping of its output. When diodes are used in the feedback loop, signal amplitude is generally constrained to be well within the headroom limits of the op-amp, such that one hears only diode clipping.
But what follows somewhat from this reasoning (assuming I'm correct) is that increases in supply voltage - conceivably via charge pumps - can take the headroom limits out of the equation, assuming the gain is not set ridiculously high. And the related inference is that chip-to-chip differences in a 250-like circuit will be most detectable when the supply voltage is kept low. You might even want to tinker with descending below +9V, perhaps via diodes in series with the supply. For all we know, forcing a stable supply down to 8V or 7.5V might result in more audible tonal differences than changing clipping-diode type. Worth experimenting with.
And FWIW, Ottawans are generally behaving themselves, with our case-count being a smaller share of the provincial case-count than our population size would predict. Stay well.
Mark