OK, so we know it was a lone T-65 that destroyed the Death Star (major spoiler there, thanks FFG!); it didn't fire a single Photon, but two Photons.
This led me to think, I hope we have an over charge option where we spend the two charges and either double the number of attack dice, or roll the normal amount of attack dice and shields can't bock it.
I mean clearly once the game mechanics puts a 'charge' on an action, we'll want to overcharge the action - imagine a boost action with 2 charges, an overcharge can use the 2 move instead.