Billy, much good advice has been given above, but to answer you question directly, and specifically this part:-
'Perhaps the Trinovids >200X have a similar spec to the Uktravids from 199X? Perhaps Generation Y of the trinovid very nearly matched the Ultravid from the same time period?'
I would suggest looking out for a 2012-15 Trinovid. This particular Trinovid was only made for a short time before it was 'superseded' by the cheaper (made in Japan) Trinovid HD, but it's widely been reported that it had the same optical quality as the Ultravid or even Ultravid HD. See this review from birdwatching.com:-
https://www.birdwatching.com/optics/2012highendbins/review.html
There are some differences that separate it from the Ultravid (as noted in the review) - slightly smaller FOV, longer minimum focus distance and slightly heavier, but in my opinion the 2012-15 Trinovid is a bit of an overlooked Leica gem. I have the 8x42 and it stands up very well indeed against my 7x42 UVHD+ and Noctivid 10x42. They may be hard to come across, but if you see one I highly recommend giving it a try!