There are already threads that started investigations on the mana gain for the defense:
According to SG: However, do note that the Mana needed for each mana speed is not the same for offensive and defensive heroes in raids.
Current theory is:
combo 1 tile (1c1) is 66.66% of a tile in offense, and End of Turn (EOT) bonus is 1.30 of a 1c1.
[β¦]
Mana gained from hits depends on current number of combo. Combo 2 hit gives 90% of Combo 1 hit, and Combo 3 hit gives 90% of Combo 2 hit, and so on.
I continued from there and did my own analysis, results shown here: