Another couple of random thoughts that have occurred to me. The stab. trim setting must be a compromise setting particularly on the -NG. The "normal" flap setting for T/O I would suggest is Flap 5, however I have over the years frequently used Flap 15, and less frequently Flap 1 or Flap 25, when the performance has required it.
Our T/O MAC trim comes from a DCS load sheet which doesn't know what flap setting we are going to use, so we use the same setting irrespective of flap setting. IIRC the "classics" had a correction on the back of the QRH to allow for different flap settings. In practice I have only ever used Flap 5 or 15 on the classic.
There are of course other load and trim sheet providers, from a manual load sheet where pax and cargo are in zones, right through to Boeing propriety tools like the OPT, some of which will know flap settings and most will be able to calculate the pax loads based on which row of seats they are in. These should be able to provide a more accurate trim sheet.
Which brings me on to a final point on how the stab. trim setting must be a compromise. Various airlines use different weight assumptions for pax and bags. Most operators I have worked for use a standard pax weight and a standard bag weight. My present mob use a standard pax weight but the actual baggage weight. How many of us, or our pax are a standard weight though?
All this leaves me to believe that the stab trim is usually "about right" for an all engines take off, but is woefully inadequate when practising an EFATO, where a big heave is required!