At Cap nou right?? I hope so even though that's laliga ... I don't believe in stadium super powers anyways but revenge it is??.
The. best thing he can do is not playing both of them at the same time just that there're no abundant resources to do that at the moment so he has to find a way to make them play together maybe that could even solve future things. Hence,he favourites players sometimes some of his boys are not getting enough playing time, now that he need them how can he know which(not like they are not good though )..
You could say yes, although the truth is that it is very difficult to achieve that objective of beating them in that stadium and because of the number of goals that are owed, I really think that Barcelona will take care of that, but it is not something impossible, if Madrid is only good enough they have to do it or try to do it so that it remains in a "tie" let's say it like that so as not to use the word "revenge", given these things we have to see things the right way, because that goal average does influence, if they remain tied then that weighs, then it would not be revenge, it would be equalizing things.