The 41 mm and the 38 mm both use the GP 3300 caliber. The one used by in some VC, Cartier, MB&F, Daniel Roth, Bulgari etc. as well. So it’s smaller and slimmer at 3.28 mm. Back in the day, it was considered almost “ultra thin”. The laureato 8010 uses its predecessor the 3100.
The 42 mm 3 hander uses the GP 1800 caliber which was actually from Jean Richards their sister company. It’s a thicker and bigger movement. All GP laureato chronos use the 3300 with the D &D module. Even the 42 mm and the absolute 44 mm.
Interesting that you find the 42 mm similar to the 15202. I find the 41 mm the one that is similar to the 15202.
Laureato chronos are 904L. The 3 handers are 306L. All APs use 306L across their steel models.
Always wondered what the appeal of 904L was in reality. Less corrosive but not they the 306L is going to rust. Also 904 and 306 are bored categories with a range of i gradients and proportions. So one brands 904 is not going to be the same as another’s.