An experiment I cannot do... gooseneck tonearms

[Inigo]

Thanks for your replies. For easy, let's call the tonearms as the similar capital letters; gooseneck old style tonearms having an u-tube at the end are shaped like a P (as in old Victor/HMV horn models). Later type swan neck tonearms are shaped like an S, as the HMV reentrants, or the orthophonic victrolas.
Gramophone-georg: you can see more what I'm saying, see the photo of the fat P tonearm by AZ. Can you see what a terrible offset? This is the very model I referred as version (3). Pity that the U-tube flip over cannot be done, as the dead end closing its fixed to the tonearm.
Henry, in the older models, the goose neck cap is simply screwed at the end of the u-tube, and it can be installed in reverse. I've found some time ago one horn gramophone with the u-tube mounted in reverse by mistake.
G-georg: I also see your point with the swan neck Credenza tonearm, the S style ones. And certainly, adding a properly designed coupling between the tonearm end and the soundbox allows you to adjust tracking errors. I also thought about this for some time, but still have not put it into effect. And I agree this coupling would be the ideal solution improving a gramophone design by simply adding a removable device, not touching the basic design of the machine. Have you ever heard of the 'lifebelt'? It was sort of that coupling tube, but straight, and made of thick rubber. This improved alignment by increasing the offset, and also provided a compliance at this point, with much benefit to the sound, needles and records.
Anyway, with Credenza-style gramophones, or the HMV reentrants, which have long tonearm and very good tracking, I don't see it necessary. Those machines have very good tracking, and improvements are not usually necessary, except little adjustments of the sbox zenith angle (roughly 50 to 70 degrees) and the needle length. These precise adjustments need to be done with the aid of an alignment protractor (search thus forum dishwasher for details), they're so subtle minimal adjustments.
About the HMV machines with S tonearms, much more has to be said, though.
The long fat tonearm models, as said, usually are designed with very good alignment.
The portable HMV 102, with fat S tonearm, has very bad alignment, especially at the outer edge of records. But this cannot be corrected, for the short tonearm is not capable of better alignment. It is a compromise in design, and clearly they decided to put the better tracking at the more difficult inner grooves, leaving most of the tracking error at the outside. If you correct the alignment for the outer edge, you would have a terrible error at the inner grooves instead, which is more dangerous. For what it its, it is the best design compromise that could be done with such dimensions.
And another story is the thin S tonearm of the 1925 HMV models (101,103,109,126-127 and the bigger ones). I only know deeply the portable 101 and the tabletop 127. These have the same tonearm, and it its larger than that of the 102, but alignment is not good on some machines, in others it looks better. It depends on the subtle adjustments I've mentioned (zenith and needle length).
Flyball: the point of this discussions is for me asking someone to make an experiment for me.
And bad track alignment is harmful both for records and for needles, and sound is worse, for the diaphragm doesn't transmit adequately all the energy taken from the grooves, much is dissipated in useless work of the groove against the tonearm itself, not producing sound, and provoking a harmful reaction of the needle against the grooves. This said, my experiment, if it can be done, is to invert the arrangement of the U-tube in P arms and examine if it improves needle track alignment.

[Governor Flyball]

I suppose the point I wanted to make is that with a heavy tracking sound box and the low cut off frequency to the mass of the mechanical linkage, I do not think correcting the tracking error at the record edge will provide any noticeable improvement. What I think on these machines is more critical is ensuring the needle passes over the spindle to minimize lateral forces on the grooves and to ensure the tracking error is minimized only at the record center. Minimizing tracking error at the inner grooves will reduce inner groove wear.