Hi BradersNolan,
There isn´t a "best tactic" because you need to adapt system for players type you have. It´s not the same playing 4x4x2 with Chelsea or 4x4x2 with Milan, just to give an example.
Tactic is good for start because you set players positions accordingly to their preferred moves/stats.
However, after tactic, you should prepare team instructions for what strategy you want. Example:
4x4x2 pressing: closing down medium/high, tight zonal marking (some players), tackling medium/hard.
4x4x2 counter: focus passing both flanks, tempo maybe high, passing mixed (use direct/long more often).
So, as i said, "best tactic" could let you win some games in a row but you´ll fail badly if don´t consider team instructions (and player ones too) accordingly.
GL
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Best tactic to use 
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