Figure a Exposed Slip up to a couple million tons capacity (3 or 4 Hughes Sections), several smaller pressurized yards (6-12 Huges Sections), for fabrication of large complex components, Engines, KF-Drives, individual Ship modules. Then you have to have some amount of workshops and factories, for a basically static facility I would say 3 or 4 times what a Newgrange would carry (6-12 Hughes Sections), and even more if you are going to be fabricating the weapons and electronics locally. I would want several (6-12 Hughes modules) just for supplies and parts. Finally your 10-20k workers and administrators will need living space, (3-4 Hughes modules with large Grav Decks, like a Snowden Mining station.
I basically imagine something like the Pavaise SDS Station, but made of Hughes Station Blocks, just a bit bigger to take the Potemkins and McKennas.