Subscription with multiple joins

[Naqash79]

I am trying to publish a publication where the data is coming from multiple mongo collections, and subscribing to that publication from my iOS app First question is, what is the best way to do that, on my Meteor Server side, should I go with Methods or Publication, moreover should I use mongo aggregation, dbref, or any other way (returning multiple cursors etc) Moreover, on iOS side, do I need to just create one entity, representing the publication fields returned; or should I have entities representing all collections?