For the purposes of ballpark, between 150-200 petabytes of unique data, probably on the lowish end of that last I checked.

it is large enough that I am wondering if the data captured by the actual physical magnetic charges has a heft, that a person could feel. obviously the hardware would fill a house or something, but at what point does the worlds data become a discernable physical reality, at least in theory

I'm betting exabyte or close maybe