What are their training speeds? I've certainly seen big big variations in training results for any 1 player.

Only NordGen data I have is after achieving 6* - he's averaging 30/60/105 (don't have much info on the 5* rate because he reached 6 before I started recording. )
Sorry ive not been recording ,just they only 3/4 skill point bar where as ive got 2 skill point per run in the past seasons.

Some 18-20 yos now trains like a 26-29 year olds, or even like an old man's training speed

Agreed my 24-25 yr olds are training at same rate as these new 18yr olds