Here is a video by Pacey explaining the differing Essence conversion rates in honour of him reaching 100,000 views on his E2 Channel.
The difference in conversion can be found in this table:
Credits to E2Economist.
It shows a major disparity between T1 and T2 properties, as Tier 2 properties have a 10x lower conversion rate than T1 properties with promised Essence.
So don't worry if you're getting a lower conversion rate than other players - you just have a different ratio of T1 and T2 tiles.