I have a similar questions.
I am playing as Reading in the English Championship, I went 20 games un-beaten and sat second in the table by only 2 points. I played a 4-2-3-1 formation but narrow, using the vertical Tika-Taka instructions, with minor tweaks. Going into each game I would make small changes, i.e. changing one of my W-S to an IF-S if I thought I could utilise the space better, changed mentality from Balanced to either Cautious or Positive, depending on who I was playing and match odds.
Then my form dropped off a cliff, 12 games without a win and now sitting 8th. No matter what I try, I cannot buy a win. The game kept saying that the fans where unhappy as I would not change tactics... so does that mean you must have two different formations, or can you have a base tactic that you can tweak.
And how do you use the opposition scouts report to amend you approach to the game? Should I change mentality or change roles / TI?