The team i would play is
--------Alves----Pique---Puyol---Abidal
-------------------Masch
---------Xavi---------------------Busquets
----Iniesta--------Messi-------Villa
With both masch and busquets playing will give Alves the freedom to go forward without us having to worry, while at the same time keeping the centre of the midfield safe as one of busquets or masch will always be there.
We will have to keep our usual high line and play the offside trap as if we sit too deep, real have the players to put in a shot from 20-25 yards.
we all know the benefits of playing Messi in the middle, so i won't go into that, but villa will have to be on the top of his game and make those runs in behind the CBs and take his chance when they come as i'm sure he will get at least two good looks.
Alves and Iniesta on the right should run Marcelo ragged and create a few good chances for us, and iniesta as well will have carry not just his shooting boots, but his scoring ones.
as for real if we can keep Alonso's influence on the game to a minimum they thats half of the job down as the rest of real's players are just "runners" with the exception of ozil who i'm not too worried about, masch/busquets will deal with him.
lets see if jose will come and play is straight up and do is usual things.
Ps, Barca playing Masch and Busquets isn't an defensive tactic, it simply a way of giving our attacking players more freedom. so i don't get the way would pep move to a more defensive system at home thing