well i would run one or the other. and both i would use the same way. i would play them only when i can use them. other wise leaving photon out invites destruction. at which point it would be useless to you. and since it does only one damage it really wouldn't be much use to play early. but that is just my opinion. i haven't tested the difference (although once i was playing a grav/aether deck and my oty was reduced to 1 hp and a spark did save my oty) and i don't have a whole lot of experience in deck building, this is based entirely on on observation