Happy that you found the answers Puzzler, you saved me a lot of typing, but thinking of a response gave me some alleviation from boredom on a boring 2 day stopover.
You're quite right in saying that the balanced field technique generally provides the best optimisation of Accelerate-Stop and continued OEI Takeoff performance to achieve the highest possible Takeoff Weight. Mind you, Balanced Field is not quite the sacred cow that many would have it to be, if Clearway and/or Stopway are available, and you are chasing maximum possible takeoff weight, then go ahead and use them. The problem is that any number of AFM documents, and the FMC, only look at the Balanced Field, or (even worse) advise that the AFM data is for an unbalanced field with the limiting weight being the lesser of the Accelerate-Stop or continued Takeoff cases.
If, indeed, as you say, your 'typical' Takeoff weight is well below the maximum, then you should have an excess of performance available for both the Stop and Go cases. Even though you are below the limits, it serves well to maximise the safety margins, and in this respect taking precaution against the statistically most likely mishap would be well advised. Accelerate-Stop accident / incident numbere far out-weigh accidents / incidents for the continued Takeoff case and utilisation of the speed schedules offering the lowest possible V1 will statistically favour the worst case. Of course, such a speed schedule reduces margins for the continued Takeoff case, but statistically you are far less likely to have a problem here.
It should be no mystery why the Accelerate-Stop manoeuvre is more fraught with danger than the continued OEI Takeoff if you analyse the in-built margins during certification. For the continued Takeoff, the margins are very generous (up to 50% excess) versus very slim margins for the Accelerate-Stop.
In my Performance Engineering tasks, my objectives are first, to achieve the highest possible weights possible, and, having done so, then set about finding the safest means to achieve those weights. (All of the techniques are safe, some are safer than others).
Regards,
Old Smokey