You're technically correct but I think rather missing the point. I got the scale wrong (guessed at the tolerances involved rather than looking them up), but obviously resolving a mechanical position to meet the actual tolerances is already a solved problem by current voice coil systems. A simplified version of the same mechanism could be applied to the line-of-heads solution I'm suggesting, considering that in both cases a comparable reciprocal mass is being moved back and forth, but in the scenario I'm proposing it would only need to be moved a millimeter (or two, or one, or a micron - all are far smaller of a movement than the comparatively huge arc swept by current head designs)
Whatever subdivisions within that bounding range are necessary to achieve equivalent (or superior) accuracy to flying head designs has already been proven to work in spite of the current designs' much more complicated and delicate arrangement.
Whatever subdivisions within that bounding range are necessary to achieve equivalent (or superior) accuracy to flying head designs has already been proven to work in spite of the current designs' much more complicated and delicate arrangement.