Apologies for the bump and also apologies for not responding to the most excellent replies. In particular the concern about differential torsion applied to the hub. That one really made me wonder to the extent that I set them aside.
The counter argument, for which I may perhaps be slaughtered, is that we know that for a dished wheel the spokes closest, shortest, to the rim have a higher tension. Drive side has a higher tension than the non-drive side. By extension on each particular flange the spokes exiting internally will, should, have a higher tension than those exiting externally. At least in a lateral sense.
This is not to say that you cannot get a valid answer by assuming that the tension either side in isolation can be set up as being equal and you will end up with a true wheel. It is saying that the difference is there and by adopting that difference you can end up with an equally true wheel.
This is what I got, on new rims, using my Park Tool adopting those differences. A true wheel. Of course as others have mentioned and as I noted myself the tool might not be overly accurate but measuring twice, more, it gets a relative answer.
However the proviso might be that my program basis its suggested tension solely on the lateral angle of the spokes. The smaller the lateral angle the greater the tension. In number terms it is a significant difference, 10kgf non drive vs 26kgf drive, but in real terms it may not matter.
In respect of torsional forces as opposed to lateral ones I am going to take an uneducated guess based on a wet finger and the method of it seems right in my head that leading and trailing spokes operate in the same direction either side of the hub, the twist makes it so, and therefore the differential tension in a lateral sense extends to the torsional sense and the hub will experience or adjust to the same twist/torsion on each side and remain balanced.
Having convinced myself that this is the case I shall make the last few tweaks and stick rubber on them, put them on the bike and see if I taco face plant myself.
Again. Thanks for the comments and other information.