Guys, the tactic that I sent to Eduardo85 isn't a 4-2-3-1 tactic, it's a tweak of Demolisher tactic, it has a 4 man D-line and a striker.
To those people who are looking for good 4-2-3-1 or 4-3-3(DM) tactics, I can say that for long time these formations haven been quite weak compare with other approaches in FM and I find that in this year FM version they are weaker than they were at any time before, they offer a very little overarching.
Please notice that I don't say that it isn't possible to win competitions in FM if you like to play with tactics that use 4-2-3-1 or 4-3-3(DM) formations, I had few long terms saves where I used tactics that had 4-2-3-1 and 4-3-3(DM) formations and with those tactics I was able to win the most challenging competitions in the game such as EPL, LIGA BBVA and Champions League but to achieve that it required building a quite strong team and even with a strong team the results weren't enough consistent on my taste

so I don't see any point in sharing tactics that use these formations.
Btw, in few moments I'll update the Striker version of Demolisher tactic (just a small tweak that improves the tactic) and also I might add a 4 man version D-line version of Demolisher tactic to the OP, I haven't decided yet.