Starting player and this event; how to be efficient?

Really new player (only lvl 69 and 1 5*). Should I go full Heroic Scrolls and with that bump up the summon prizes (getting orbs + bones)? Or should I ignore that and go full orb?

Have 2500 gems and 19/20 in the summon prizes.

Edit: There are quite a few factors: More scrolls means more fusions. Scrolls have a higher chance of getting a 5 star during the event. What are the rates for getting a 5* from orb and which from a scroll?