The 42mm 4th generation is the one to use. Preferrably the later version, as the earlier version won't accept the bezel without modification (the later ones will accept the gen bezel as a 1:1 replacement).
Later version-
-Gen dial
-Gen hands
-Gen bezel complete
-2892 DW
-Gen bracelet complete
Earlier version-
-Gen dial
-Gen hands
-2892 DW
**Bezel is not a direct fit
The POrikaa has some slightly different dimensions- The dial, crystal and bezel are all a bit larger than the 4th gen, so swapping in gen parts may not be as easy due to the size differences. I've not experimented on a POrikaa case yet, so can't say for certain, but judging by the way the gen parts fit the 4th generation case, I can say that it might not result in an optimal manner.