Wanted to share my thoughts on this while we wait for the next SSD article on the Assault Prototype.
Using the ISD (8") as a baseline I've come up with some ship measurements.
Resurgent-class Battlecruiser- 14.6"
Secutor-class Star Destroyer- 11"
Lucrehulk-class Battleship- 15.9"
MC85 Star Cruiser- 17.2"
Bellator-class Dreadnought- 36"
Now obviously the sliding scale of Armada means that these won't necessarily be the lengths listed, but this gives you an idea of how big these ships would be on the tabletop. So the question is where is the line between Large and Huge ships? I believe that the Secutor-class is likely the largest ship that can be considered Large and not Huge, as the ISD is already hanging off its own base.
If anyone was curious:
Executor-class Dreadnought- 95"