I was playing an Epic game and I wanted to get a sense on something.

With this, if I have, say, three Quad Laser Cannons equipped:
(A) Optimized Generators can be triggered when I assign energy to the first QLC, interrupting the "assign energy step" for the moment, and giving me two energy. Then, I'd proceed with the assign energy step and allocate energy (whether old or new) to any remaining Upgrade cards that I chose.

(B) All energy assignments must be chosen first using only previous energy, then Optimized Generators triggers after I've allocated all the energy I've assigned.

I was personally in the (A) camp, but I could be wrong, other folks might have a different sense of things.

I would go with A too since this is the way I ve been playing it in a while.

Another vote for A. There are several precedents for one trigger interrupting something and when that is finished you continue where you left off with a previous trigger.

A. Interrupting is a legitimate thing to do, and all events in x-wing happen sequentially, nothing is simultaneous, so there's plenty of space for it to happen between one energy assignment and another.