I'll also point out that raw numbers don't mean that much.
Finished actual dimensions can be a good start, but that assumes the same basic profile of each quilt.
My quilt profiles are highly shaped, and actually wider laterally in other places than at the top of the quilt, where as most of them start wide and either maintain that width half the length of the quilt, or immediately begin to narrow.
People use different footbox styles, which may require different widths and translate differently to roominess, etc.
Katabatic's quilts are highly shaped also, in a totally different way than mine, which makes them uniquely ideal for back sleepers in my opinion. Which is why I recommend most back sleepers toward their wares.
I specialize in comfort for the more acrobatic sleep styles, and as such, design the profiles to be optimal for that.
Anyway, all this to say, it's a complicated issue, much more than just the flat dimensions. Couple that with the fact that some people use raw-cut numbers (which don't represent the finished dimensions very closely at all), or the mysterious "girth" spec, which I haven't been able to nail down a standard definition of, and things start making even less sense.
My recommendation: If you're looking to a buy a quilt, figure out *your* dimensions as much as possible, and more importantly, your sleep style and requirements for comfort. Then ask other users for some recommendations. If you're trying to make a quilt, well, just go ahead and make a basic design, and then refine the next one, because it's a long road to perfection. How long? No clue, I haven't made it yet.