[The 4231 Explained]

Just now, Cleon said:

It'll become more clear when I do the analysis and comparisons. However I used a SV because I need someone who still plays like a MC and will venture further forward and offer support. A DLP wouldn't do that.

The support duty is because while he is shielding the defence, I feel a defensive duty will make him too deep and disjointed from the other DMC. I want them playing as a team. Plus I want them to shield the defence yet win the ball in the early parts of my own half.

And yes you can use any role you wish if you get the balance right.

That makes sense, so the support duties and SV are picked because they make sense in relation to the style of play you want with the tactic?

[The 4231 Explained]

Will be following this as I am attempting to create a 4-2-3-1 with Sevilla. I have a few questions though. 

Why did you use a SV instead of a DLP?

How come there are support duties for the holding player that will shield the defence? is this because you have two DMs in front of a back 4 meaning they will shield the defence by default due to being positioned there?

Is it possible to use an Advanced Forward in a 4-2-3-1 providing you get the roles right around him, Or is it simply down to the fact that role in particular isn't optimal for the formation as a whole?