Q: Is a structure bigger than a 2-A structure Low 1-C by default?
No, the default assumption is that this is not the case. "Bigger" could mean having more 2-A structures and, as explained in greater detail
previously, having more 2-A structures, or even infinitely many 2-A structures, unless
uncountably infinite many, won't scale above a single 2-A structure in size. This is due to these structures actually have the same size as a baseline 2-A structure. It is, however, possible to at least achieve above the baseline 2-A power by upscaling from other characters who've performed 2-A feats or of the feats themselves, rather than by affecting 2-A structures containing other 2-A structures. However, if "bigger" is indicated to mean a size difference that makes the structure
qualitatively superior to a 2-A structure the structure qualifies for Low 1-C unless the fiction specifies otherwise.
To elaborate, a structure larger than 2-A meets the requirements for qualitative superiority over them if it either explicitly mentions an uncountably infinite number of universes or has portrayals/statements of being bigger in size than 2-A structures to the point that even infinite multipliers on top of the size of that structure are of no relevance to it. Multiversal structures past Low 2-C frequently have a distance of unknown length along a 5th dimensional axis separating them. That isn't automatically Low 1-C, as for Low 1-C the distance must be known to be of non-insignificant size.
In that regard it is important to consider that, by its nature, it is not possible to accurately depict 5 dimensional space. As such depictions of the multiverse are usually not to be understood as accurate representation of the distance between the universes, but rather just qualitative analogies of the multiverse's structure.
As usual, evaluation of any additional evidence needs to be done case-by-case.
