Best practice how to use Access Rules and Xpath constraints without (much) loss of performance

On a object we have set access rules and Xpath constraints. On top of that we use extra Xpath constraints (3 levels) to retrieve certain data of that object (apply entity access = yes) and do a count for optimization. In our application we have to do a retrieve of data 30 times.

We see that this combination is pretty slow.....

What can we do to improve performance without denormalizing data?