Is the approach to maxing out deity units the same as others (start with 10% chance, then move to 25% after +2 or +3)? I have a surplus of SS units that to throw at them just to make the process easier, but I'm pretty sure that's not the thing to do. Main reason I haven't been combining SS is because I just don't have the feeders for it.
for diety you need to burn 1 essence every attempt at an upgrade so most ppl use only S rank so 25% +fail bonus, otherwise you would waste a huge amount of essence using A rank allies