This is an interesting project and it is always nice to have an alternative to replace these displays that are becoming rare.
Sure it's a good idea to start with something simple to validate the concept and the emulation. Mechanically, it can be quite complicated especially on the 80B, it is not only the size of the display that changes but also the mounting place and the connector.
Subsequently, it would be a nice evolve to do the same thing for all 80B, and why not, also for the first SYSTEM 3
The first SYSTEM 80B actually used smaller displays.
The MA-644 boards first used VFD tubes from ITRON - FG209M2. Then, FUTABA 20MY-01Z tubes were mounted on MA-644F cards. Their pinout was different, but visually it was the same. Both boards were using a flat connector and the 10941/10939 chips.
Later, Gottlieb used larger displays on MA-999 boards.
This is this model, you try to emulate. The VFD display was then an ITRON FG2013B2 and the logic 10941/10939 is retained, but on the other hand the connector is now a model with spikes. Note that, there is a special model of the MA-999 board that has been used on the NIGHT MOVES cocktail table. The board is the same, but for mechanical constraints, the connectors has been mounted on the back side.
The same ITRON FG2013B2 VFD tubes were used on the first SYSTEM 3 in MA-1361 boards. However, the logic no longer uses the 10939/10941 and the connector was switched for an HE-10 format. This obviously does not work in the same way, even if visually it is identical to the last 80B.
It's funny to see that just like for SYSTEM 80B, there is a derived version for SYSTEM 3 named MA-1431. It is still the same board, but used on the CARRIBEAN CRUISE cocktail table, with (again) the connectors mounted on the back side.
To avoid polluting the topic, I will not put my photo here, but the sizes of the displays/boards can be compared here: https://www.flipprojets.fr/Testdisplay80B_EN.php
It can be noticed, that the size of the boards is identical, as well as the location of the fixing holes. It is clear that the connectors are also different, but as the tube is not centered the same, the boards are not mounted exactly in the same place. Likewise, the cutting of the display window in the backglass is different according to the models of 80B.
Of course start with the simplest, but keep in mind that it could evolve.