I do think you need a Minor YG.
We will playtest this Sunday with the minor in India of course, but if this game mechanic proves to powerful… a small tweak like removing the Calcutta factory altogether would be an option.
How about introducing the “Medium Factory”. The rules would read
“Cost 15. Upgrades a Minor Factory to a Medium factory. Medium Factories can build up to 6 units. Medium Factories can only be built on an originally controlled starting territory that has an IPC value of 3 or more.”