I think part of the appeal of pre units is the amount of sleuth work necessary to get valid information. It's something I have enjoyed doing over the years. When I began this trip, there was no such thing as the internet and not even a library to go to for this info. Most of the info I got came about through networking with fellow enthusiasts. For example, when I built a '59 Bonneville, I knew several others building them simultaneously. It was me, Cliff Rushworth, Buzz Walneck, Gale Searing, Tom Horn, and someone I can't recall at the moment. We shared info and parts. It was great fun I have to admit.
What I find most interesting is the no two bikes came out identical; all had significant differences between them and we all thought we had nailed it.
I never showed that bike although I had several invitations to do so. The fellow I sold it to showed it at Del Mar and won the Jimmy Phillips award for it for best Triumph of Del Mar that year. It also won best British Bike and my T110 came in second.
But things have changed. I think the judges today are better informed, or at least they have access to information not available to past judges.
So, I would suggest you do your due diligence on the issue and if after some time you never get any satisfactory answers or evidence that perhaps the judges at shows won't either and you can mark that one up as a win.
I think it's painfully obvious that Triumph themselves often provided faulty info on their own products as it seems as though they just couldn't keep up with it all.
So, with regards to your magneto's original configuration I would go with what you have. I don't have any reason to suspect that T110's didn't come with both manual
and auto advance and that a significant amount of them came with the Wader mag as well.
Also, I would think that there must be a NOS cam ring around somewhere. If you come up short, I would contact one of the magneto specialists. They may have hoarded the majority of NOS parts for these mags. A used one will likely be worn and cause a timing variation between left and right sides. This can be addressed with some stone work.