[Astroking112]

As another potential dial to tweak, we could also choose "after rolling defense dice," but that would be much stronger.

As a starting point, I like "before rolling defense dice against a normal attack" the most from those three. I think that before attack dice is more prudent, but from a casual standpoint, it makes sense that the decision is linked to your roll instead of before your opponents', and I can see some bad feelings if you forget to declare that before your opponent rolls attack dice.

As yet another idea for timing and power levels, how about if the automatic shield is applied to the first normal attack against one of your units each turn? Functionally similar against heroes, but it gives squads more of a leeway to come up with a way around losing too much firepower.

Ironically, whereas the Glyph of Power really benefits armies that take a lot of smaller turns, this glyph will hurt them the most since they'll be facing more automatic shields. Just an interesting tidbit to note there.