I wish people would stop talking about Probert's intentions as if they mean anything, the saucer rim is two decks, end of story. It wasn't a retcon because the rim was never established as only one deck.
I'm sure many people intended many things but if it doesn't end up on screen it doesn't matter.
This is
not about what Mr. Probert intended or not, but the final scale of the 6-footer
as seen on screen.
The 6-footer has at least two external features that enable us to conclude the correct in-universe size, i.e. the windows of the Conference Lounge at the back of the bridge and the diameter of the port docking port (i.e. "11001001").
According to those there'd be only space for one deck on the saucer's rim of the 6-footer, but that wasn't considered when the idea of Ten Forward came into being.
Apparently the
rim became a lot thicker on the 4-footer to compensate, I still wonder why they didn't use the four large windows above the Captain's Yacht for the location of Guinan's bar, instead.
Bob