If I were you, I'd download the spreadsheet that shows the training simulator. In there you will find a tab showing coef. It will give you an idea of how the training values work.
For instance two position training one on one guards/fowards train a lot of skill points per session. However, outside defense is probably all-around the best skill but trains the slowest overall.
Anyway, I wish I would have started with some idea of various training speeds
Then I probably would have kept my HOF instead of selling him for easy cash ha!