Of all the Orisha Elegba is one of the most central & one of the most powerful.
Esu/Elegba is chance/luck. He rewards those that make sacrifices and punishes those that do not. He is the duality inherent in the universe and at the same time he transcends it. He is the custodian of Ase or divine power/command. With Esu/Elegba on your side ANYTHING is possible!
A Tier 2 offering adds a simple divination to better pinpoint exactly the materials that will best help you to enlist Elegba's help
A Tier 3 offering adds a sacrifice that Elegba loves
A Tier 4 offering is really a Full Ifa Divination Gig and the appropriate Works