[quote=@DocTachyon]What do you mean by size and force applied?[/quote]I mean exactly what I already said. I can not make it any more simpler.

[quote=@DocTachyon]Is there a maximum size?[/quote]Yes. Larger than her smaller than a two story house.

[quote=@DocTachyon]How much force would it take to crack the sucker open at her max effort?[/quote]As I said before it would depend on the size of the shield. You will have to be more specific or I can't help you.