Improving Players

[edhdurham]

Hi,

I have taken over a lower league team and rather than look to move on average players and sign better ones, I thought I would use the pre-game editor to just improve the current squad.

Are there are rules I should follow? 

I was thinking that if I improve a players PA by 10 points, then I should also improve their CA by the same margin?  I dont really want to improve individual ratings, just their overall stats.

Thanks