I posted a 1 week result earlier but here's an overview of 6 weeks training OS.
I rated the skill and note it down every week.
Player 1 (18 yr):
JS 5,5,5,6,6,6 (+1)
JR 3,4,4,5,6,6 (+3)
HD 4,4,4,4,4,4 (+0)
Player 2 (19 yr):
JS 4,4,4,5,5,5 (+1)
JR 5,6,6,7,7,7 (+2)
HD 4,4,4,4,5,5 (+1)
The second one might have gone slower because of age or being ahead already in JR.
Trainer is lvl 7
Crunchy! If you eat fast enough