Pam 111 series question

[mg18]

Hi everyone, I just had a question about the whole "series" thing. I know that the letters indicate what year the watch was produced in, and I also know that up to a certain letter the 111 were sausage dials and then switched to sandwich dials. I know that CG used to be polished now brushed, and I know that the movement had panerai stamped all over it and now it doesn't.

However, I have had trouble finding out what the differences between let's say a 111 J series and a more recent N series apart from the year it was produced.

Can anyone shed some light on differences from J series 111 and onward?

Thanks.