Formations, Well probably due to my teamusually being stronger than opponents, I don't really need to change tactics much, so I leave my team mostly in classic 4-4-2, possibly down to the players that have been available from the scout, Never seem to see a good AMC or DMC that meets my scout buy criteria for age/quality. But, when qualities come closer to mine or higher than mine then I do have to give the game a bit of thought on what my opponents doing, If there quite defensive, then I will want to use an attacking formation. If they are quite attacking, then sometimes I can be on the defensive or setup for counter attacks.

I faced 4-1-4-1 opponent stronger by 8 quality in the cup semis last season, at home played 3-5-2 but lost 2-1
2nd leg away I started 4-3-3 was losing 2-1 and then went 3-4-3 attacking and won 3-2 and went through on away goals.
Final faced 4-1-2-1-2 narrow diamond opponent stronger by 2 quality and played 4-1-3W-2, draw 1-1 but won on penalties.

So with the cup ties vs stronger opposition last season, tactics can certainly play a big part in Top Eleven.