I understand your doubts about whether Venini could provide a precise attribution to you from photographs. However, you face the same issue when you try to identify your piece using photographs in books. What I was suggesting was that you were more likely to get useful information from Venini than most other sources, unless you pay a fair bit of money for that advice.
You may be like me in that you're reluctant, for a number of reasons, to approach a company. Yet I've found some companies, including Venini, only too willing to help. You find out more in a simple email than you would in hours of internet searching. When I was in Murano, I went in to Venini with pictures of a chandelier I had bought second hand. The person spent about 45 minutes with me trying to ascertain whether it was Venini, and apologized as the person who would be able to tell was on holiday at the time. She even gave me a catalogue of Venini lighting to take away. Another person I advised to contact Venini found them very helpful in identifying a chandelier she had and even produced some replacement parts for the chandelier.
In your case, we're talking about an important piece of Venini history, and so I think they would be interested in getting involved. Of course, I could be wrong, but what have you got to lose, only the time composing an email shorter than the ones you've posted here.
PS I'd love to see some photographs of the piece, as, I'm sure, would others on the board.