In reference to the other reply (not why I posted really), but the circumference of Hyperion redwood is between 47 and 48 feet.
About the additional above about Pando / Aspen:
In Prairie Creek, I saw a stand or row of curly redwood that are good evidence that comparable or larger redwood clonal stands may exist, in relation to the Aspen colony. I recall about six to eight big redwoods in the row, likely all connected root to root. Others off to the side may be connected too. That was not related to our tree measuring task, so we just moved on.
The clonal stands are a tangent we don't get involved with. Too much forest, too little time. And not much profit from the hunt anyway.
Measurement on an individual tree and single main stem basis seems like the way to go.