I think the best spot for Cuadrado for the TEAM'S sake is on the left wing in a 4-3-3.
Look, Italian defences are not stupid. They give Cuadrado avenues to pass them but they're in non dangerous areas. When we see Cuadrado on the right wing beating players, it's because these defenders are ok with him beating them to the outside because he's shown his whole career that he's not dangerous putting in crosses.
But on the left it's different. He's still going to get doubled up and they're definitely going to show him the outside. But this is where Evra or Sandro come in. They will have so much space if Cuadrado can cut inside and play balls back outside for them.
This is Cuadrado's best scenario for me. In the 3-5-2 as a RWB he's fine because he hustles. But offensively there's no one behind him to overlap since he's the widest player in the formation. Against Palermo there were a couple moves where Sturaro had space in support. But this is obviously so sub-optimal, to have Sturaro benefiting from the space.
As a RW in the 4-3-3 he's reluctant to use his teammates on the outside because he wants to occupy that area himself. Always drifting into that space because it's the easiest area to find space. Always cutting outside because he's one-footed.
But I don't see him ever getting the chance at LW in a 4-3-3 so I think he's a RWB for now. Or a SS when we are countering late in the match. Allegri gave him a shot in the 4-3-3 but it was a failure. On a loan he's fine. In a vacuum, is his talent worth 20M? Probably. Is he worth 20M to the team? No.