[Aubrey N Bruneau]

Perhaps just MY thought on it... ? ? ? ... but I don't see it so much as "trial and error" ?
The "blessed" dyno sheet should help us SOMEWHERE !
Personally, I study the torque / horsepower curves ( we all know that single peak numbers don't do much, if there's no "support" before and after ). I calculate % RPM drop at each gear change. Then apply that operating range to my dyno numbers, and determine what start / finish RPM points, show the highest average HP between them.
To me ?... just mathematics. Also, as I see it, the greater the drop in RPM, the higher the shift point would have to be, in order to remain in the best average HP.
The only "trial and error" after this, would be to possibly drop your shift RPM by a couple hundred, to help the engine fall into the thick of it's torque curve.
I dunno ?... again, just my thoughts.