The absolute cramped maximum of 737-300s (which Jet2 has) is said to be 149. The same absolute maximum for CS300 is 145. Not a big decrease.

Very fair point. And thinking about it, I have a recollection that the C-300 may ahve been advertised with 149 seats. Well spotted….I must be having a blond day (and look at me praising chornedsnorkack…it must be a cold day in hell :dev2::p)