I've played 10 friendlies before league start but didn't help me
Friendly games coudn't help me much to have solid conclusions about my positions - setting of my players.
Here, we have two sizes - my team and opponents team. If I want to measure my team, the other size must be the same every time, so the other team must be the same, with the same players/formation/orders and morale/condition so I can observe my team how is reacting. It's not easy to do it with some other players of the game (for many reasons).
I have another team but now is to low in q comparing with my main team, so if we add the random factor/ roll dice of the game, I cannot have anymore trustful results.
Maybe can help for some to obvious things - a player that gets rates of 4-5, but not where to use a ST or DC or MC (left-right position) or a corner/ free kick taker.