Well I checked history related threads but all info provided there is speculations...
I
I 've made a test, somewhere here
https://forum.topeleven.com/tutorial...-trainers.html
but don't remember exactly where

Also @Svanberg made a test. I think it's here
https://forum.topeleven.com/tutorial...ng-system.html

Friendlies and training have similar results (if players skills are balance)

I played few friendlies and noticed that I get more %increase versus tougher opponents so I will focus on playing similary strong teams..
wrong conclusion.
Ok, you 'll miss some blue packs. Not a big deal.

Last game I gained +24% total increase it was win after extra times so condition lose was around 15%
At extra time of a game, you loose more condition but gain more.
But remember that with High pressing and mtm defense, you also loose moore but gain nothing extra.