Hi.
As mentioned elsewhere, I've just started to try deck-building with the core set. Dual-sphere is logical with only the core cards, and looking at the ones available it seems to me that the best way forward (at least to start with) is to have a single Spirit hero, and two Leadership, one of whom is Aragorn. This allows the use of Celebrían's Stone ("If attached to Aragorn he gains Spirit") - giving the opportunity to double-up my Spirit resources.
Firstly, does this make sense as a tactic?
Secondly, without similar cards in the core set, would there be much to gain in trying other spheres instead? Of course I'll try eventually, but for a first attempt at deck-building...
As an aside, I may have to invest in the Shadows of Mirkwood cycle just to get similar "resource smoothing" cards. Are these ones that generally make it into most peoples multi-sphere decks?