I'm suggesting a minor alteration of shipyard expansions, continuous expansion easily outpaces large chunk expansions making them basically pointless, I imagine it should be more efficient to retool at once, also remembering that there is a major downside which is you can't cancel mid expansion like you can with continuous.
I propose making larger expansions increasingly more efficient, not game breakingly so but enough to justify using them over continuous, also I suggest seriously nerfing the efficiency of continuous, maybe just a flat 30% reduction over a standard 1000 ton expansion, the larger chunks getting minor bonuses, maybe just 5% faster for each level? And maybe add some larger chunks too, 2-,000, 50,000, and 100,000 ton expansions.