Need help with player stats.

Ok, heres the thing, i've read a few topics before regarding player stats, mainly for those of created players, now I like to make my team up or just me for a random game.

I came across a guide so to speak, which talked about some of the masked stats to judge potential signings off, and thought to incorperate it into making my player.

The one that is of confusion to myself is Temperment.

A few guides/walkthroughs of this have said disregard people with 14 or higher, now before this i've auto set to 20 to skim over, just like all stats on that page except controversy. Now i've had zero problems with this.

Now to add to this, I've downloaded FMTRE the in game editor (mainly to help edit things like positions of my created players (as a lot of the time, in fact all the time, my players mainly the defenders, who I set as a DR or DL, come out as DRL (Even though they have 0 stat set in the option for the opposite to what they should be and what I made them as).

It was wondering about the Temperment option to see what it would be set at for the best player in the games, and well clicking the Legend button which sets all the players stats to the best, it puts This particular stat to 20.

So heres the main question thats bugging me.

With regards to Temperment as a mental and hidden stat, but when creating a player for the sake of myself or my team, is this best high such as 20 or low such as 4/5?