Hope you haven't already done your math, but at a 520 gear level here are my calculations:
Spammed Physic (400 potency) for an average heal of 20822.65. Then took the average of each of those spells divided by 4 to get the 100 potency average which was 5205.66. Took out all crit values
Did the same for Eos. Embrace is a 150 potency heal. Average across all heals minus crits: 5304.4
Normalized to 100 potency value average: 3536.266667
3536.266667 / 5205.66
.67931 or 67.93%
Adjusted to 100 Potency spells, Eos' heals are ~33% less than ours. This was a small sample but seems to track.
