does a component need a size greater then 0 to be hit?

[PvK]

Why is the subject labelled "(OT)"??? This is definitely on-topic.

The point is that there are two different values: size, and structure. There is also what some might call a "logic error" in that structure, not size, determines not only a component's resistance to damage, but also it's chance to be hit. If structure is zero, it'll never be hit, and the unit will be indestructible. Size has no effect at all except during design.

PvK