That Diplomat article is very informative, I didn't realise the smaller hall is the paint shop. Anyway looking at HI Sutton image again I think the new hall is 2 x 'bays', which means up to an additional 8 SSN or 2 SSBN can be constructed at once on top of the 12/3 in the existing hall.That's the summary of your post, the rest is zero or "I dunno lol". Take a look at how many ships China launched between 2015 and 2020 and examine whether what you just wrote is reasonable.
The numbers you responded to aren't random guesswork and "I reckon" like yours. They are measurements: